Day bag for plane -vs- day bag for sightseeing

I take my carry on on the plane which contains my day bag carefully folded empty inside. The day bag comes out and is used when I plan on spending most of the day away from my hotel. Works for me.

This is what I use for both tasks. Just not as full when day touring

https://www.eddiebauer.com/p/82300168/stowaway-packable-20l-daypack?sp=2&size=ONESZE

It has an inner pouch for my ipad

My "daybag" is just my purse. It's somewhat large for a purse, smaller capacity than a backpack. When on the flight I put it inside a slightly larger tote for room for a few extra things I will want on the plane but won't fit in the purse easily. Examples might be my ipad, a magazine, big water bottle, food, things like that. The tote is the kind that folds up to smaller than your fist, so once I arrive I put it back in my suitcase and just carry the purse around.

I have a tote bag that has my Dopp kit, 3-1-1 bag, meds, eyeglass cleaners, spare glasses electronics and my Civita bag. The Civita goes with me everywhere once in Europe, the tote bag stays behind.

Like Mira, my day bag is my purse- a roomy messenger bag that's big enough to carry what I need for regular days away from the hotel. But it's not my personal item for flights or trains. For that I use a medium size duffle style gym bag. It's big enough I can use it for overnight trips away from home.

I use the Civita Day Pack for the plane and the bus - if on tour. I use my sling-style pocketbook/purse for everyday augmented by a Free People shopping bag. You can get this free with any in-store purchase from Free People, but it looks like there is a health resale market for them. I have many. These are a lightweight cloth (maybe linen) with a single handle that can hold an immense amount of weight and a lot of stuff for its size, but it folds up very small for taking with one. It can be worn on the shoulder or tied around the wrist even. I almost always have one with me. There is a much larger size which I rarely use. Took this with me to Christmas markets in 2017 because I never knew if I would want to buy something.

PS, the Civita Day bag is wonderful. It held a down coat when I last traveled with it. Plus lots more typical stuff.

I take Mira's approach but also have a packable bag made by Envirosax I carry in my purse. I use it if I buy something when I'm out and about. I think it's nylon. It's unstructured and very lightweight but sturdy enough for my purposes. I wouldn't use it as a carry-on for the plane with a bottle of water, last-minute purchases, etc. I shopped online and was able to buy a package of 5 or 6 Envirosax for a good price; I gave some of them away.

My Travelon purse is my day bag. The large shoulder straps, various pockets that clip and lock for the camera and cell phone, tour books and then side pockets for a full size water bottle--works for me. Note that there is no more than 5 euros in this purse. All monetary things are in my money belt. Since it's soft and foldable, it goes into my suitcase. My carry-on backpack is my alternative but is generally only used for the plane and contains the computer, camera, cell phone and other trip necessities.

The day bag I take on the airplane is the SAME day bag I take with me every day whether I am at home or traveling.

I usually rely on pockets for sightseeing -- cargo pants and a vest (I'm not trying to "blend in"). Admittedly this is easier for a guy. I got a flight bag from our host, which I like despite having his name all over it. That works for bus and train rides too, and for sightseeing if I need more space than I usually do.

I also have an Eagle Creek belt pack that rides on my left side, where I can keep a hand on it if necessary. It fits into the flight bag but I keep it at my feet on the plane, with the flight bag overhead. (Yes, I check the roller bag.) It will hold daytime supplies, a small water bottle, and such but I don't usually carry it around except in airports and stations.

The Civita, and Joe's Eddie Bauer pack, are so light you could just pack them in your suitcase (checked or not) for flights and use them for sightseeing on the ground.

I use the same strategy as another poster above me. I pack a flattened bag as my day bag for sightseeing. This method doesn't work for everyone, but it's done wonders for me & my travel.

My airplane carryon bag CAN be used as a sightseeing travel bag, but only if I empty it and have a lot of wasted space.

My sightseeing bag is a LeSportSac Everyday purse but it's not big enough for me to take on the plane. I use a LiteGear day pack for that altho I might switch over to a zippered Tote bag for my next trip. I do carry food and water on the plane but I don't carry water when I'm out in a city. There are plenty of places to stop and get something to drink and I generally need to sit down by then anyway, lol! I also would be a nervous wreck with a day pack on in a city. Just too much opportunity for theft when you can't see the zippers all the time. Carrying the LeSportSac crossbody I can keep my hand over the zipper pulls when I am in a crowd.

I pack my LeSportSac in my suitcase for travel and just have the day pack and my carryon size roller bag.

I use ricks civitas day pack for both plane and day pack. I often carry my lap top in it on plane and there is plenty of room. I was wondering if you are trying to bring everything for daughters too. If so, one thought is have them bring their own back pack.

I also have a very small travelon cross body purse which I carry passport, credit cards, money, phone, ect. I wear it even with the back pack and it works well.

I use a Pacsafe Vibe 325 for both and love it!

RS Euro-tote for the plane. Civita for walking-around and train rides (carrying snacks) -- Civita rides in the roller bag.
Also one (or more) fold-up nylon totes from Monoprix or Ikea or Rume (the latter says it will carry 50 pounds!) for short shopping trips.

My plane personal item is also too big for a day bag. My system is to take a museum gift shop synthetic material tote that folds from a tiny, tiny flat pouch to a roomy 14 by 14" for museum and city touring days. I use hidden pockets and a very small crossbody for cash, cards, phone. If I am hiking Baggalini makes a zip flat small backpack akin to the Civita backpack. Both go in my carry on bag.
I like to keep the small crossbody in the personal item bag on the plane, so it's ready to go and also accessible.

I found a perfect solution.

I fly with a carry on and a Civita day pack. And a crossbody purse.

The Civita day pack holds water, snacks, itinerary folders, reading material, phone accessories, ipad, etc.

BUT, when we arrive at a destination and plan a day of walking or hiking, I have a small fold up Zomake nylon backpack.
I throw anything I need for the day in this - an umbrella, snacks, water, etc.

This way I don't have to reorganize my Civita (which is packed for the entire trip) for a day trip !

Amazon carries numerous types of these portable bags which collapse into a small space.

Tom Bihn’s Co-Pilot bag is the perfect solution. Handles all of my in cabin needs and leaves enough room under seat for my feet.

It works incredible well for urban sight seeing,. I hauled it around Paris and Seattle for several days and never had an issue with it being too big. I actually greatly prefer this to carrying a backpack in an urban setting. I Spent several days walking around town for 10 hours or more and was never uncomfortable.

I do bring a different day pack (osprey) if extensive hiking will be involved, such as in the Dolomites. However, I would not hesitate to take the Co-Pilot on shorter hikes such as the Cinque Terre.

Like several others have mentioned, I take two bags. On the plane I carry a lightweight Le Sport Sac daypack (backpack ) and inside that I put my crossbody purse when boarding the plane. The backpack is roomy for plane necessities and comes in handy on the RS bus if you are on a tour.

For sightseeing I only carry a nylon type, flat shaped, crossbody bag/purse. My current choice is one made by Tumi since it is nicer and big enough to carry only the necessary items for sightseeing. At home I like the Le Sport Sac crossbody purses, but they aren't big enough for long days of sightseeing. I sometimes wish I had a bigger day bag, but try to avoid that because for me when I load too many things in it, it becomes too heavy to carry around all day.

I take my LL Bean lightweight daypack on the plane. My Baggalini purse is inside it. Then when I’m out for the day, I’m just carrying my purse. My purse is small and wouldn’t hold a water bottle. When I need a beverage, I stop at a cafe or pick up one at a shop.

Nope.

My seat side bag is larger than my day bag.

I use a Sea to Summit packable sling bag as my seat side bag. I also use it as my “bus bag”
When I’m out and about I use a cross body bag. This is large enough to hold a packable rain jacket, a water bottle, my phone, a power brick, a scarf, and a working wallet with a days worth of money.

The sling bag is a keychain bag so it stays in my day bag in case I want to go shopping.

I am terrible at this — I always pack bags in my bags!! I always need a big bag for carrying on my essentials — but I don’t want to be saddled with such a big bag when sightseeing. So part of my luggage is always . . . a few bags. I would say “a bag or two” but it is always at least two and quite often more!!! Because I am so afraid of not having the “right” bag at my destination!

Arggghhhh

I carry a Tom Bihn Maker’s Bag as my personal item and a Tom Bihn Side Kick as my day bag. Everything important gets leashed inside using organizational pouches.

For plane or train travel, my Side Kick is nested inside the Maker’s Bag and holds things that I want to access during the trip, so I pull it out and tuck it in the seat back while I’m in transit.

Oh, Kim, I'm the same way! I always seem to have at least 2, if not 3, bags packed in my bags. Fold up backpacks, shopping bags, a small purse, sometimes a foldable duffel. I think it is an addiction.

Addiction or hobby collection? Hmmm. Like stamp collecting, watches, coins, antiques, art, etc.. I think some form of gathering and hoarding - I mean collecting - may be hard wired into our genes.

Patagonia Refugio 25L backpack (bright red) for everything except what goes in my pockets or stuffed into the MLC45 soft suitcase. The contents of the backpack change slightly between travel mode and excursion mode.

What Jean of Mill Creek said,

" ... when I’m out for the day, I’m just carrying my purse. My purse is small and wouldn’t hold a water bottle. When I need a beverage, I stop at a cafe or pick up one at a shop."

My airplane personal item is big enough to put my little purse inside along with the other necessities of plane, bus or train travel, but too big for a day bag. Over the years I've realized that I really don't need a day bag when sightseeing anyway.

I can take my Sea to Summit Sling Bag if I need to carry a jacket of some kind or I think I'll be buying anything in places that don't provide their own.

For me the danger of carrying a day bag is the tendency to fill it up with stuff I really don't need to lug around. And you often have to check it at museums. I've never had to check any of my little purses anywhere.

I had the same problem as you. In my case, I carry a medium-sized backpack for the plane in conjunction with a rolling carryon for the overhead. But they're kind of large for sightseeing as a day bag. The Veloce bag sold here solved my problem. Not too big, slides over a carryon's handle, expandable, and can be used as a shoulder bag or backpack. I used it as my personal item on a trip to Paris as well as my day bag tooling around town. Not too heavy but still holds a fair amount of stuff. Frankly, it's one of the best luggage purchases I've ever made. (No, I don't work for RS;)

I use the same crossbody bag for the plane and daytime sightseeing, but for each it would be packed slightly differently. I can’t imagine having to find a cafe or store everytime I need a drink when sightseeing, so always have my hydro flask water bottle with me. Sometimes you are not near cafes and restaurants either. I also wear a fanny pack around my waist and I keep my phone handy there. Yheah, I don’t look fashionable at all!

I'm a "bag addict," always in search of the "perfect bag."
On the airplane, my usual two items are RS' Euro bag, which goes into the overhead airplane bin. In that, I have a fabric bag which contains items I'll need for the overseas flight. I stitched velcro across the top between the two straps to prevent items from falling out. My handbag/purse is my second item.
I've previously used the Rick Steves Civita daypack, but it is kind of bulky to fit into my suitcase. So for my last trip, I took an Eagle Creek backpack, which folds into a pouch, packed into my suitcase, for my daypack.
https://www.eaglecreek.com/shop/packable-daypack-ec0a3cws?variationId=010#hero=0.
It has a water bottle pocket, and (sort of) safety feature for the zipper, although I didn't have anything of value in my backpack. Just my map/guidebook, snack, jacket, umbrella, etc. I especially like it because it isn't very wide, so items were better distributed rather than piling at the bottom. I wasn't sure how comfortable the backpack would be so before I left home, I stitched shoulder straps to it. Not sure if that was necessary, but I wore the backpack every day with no discomfort.

I have a backpack that I take on the plane; but before boarding, I have a small reusable shopping bag about 10X8X4" that I take out.
I put into it my iPad, book, snacks for the flight, water bottle, a small freshening-up pouch, and a scarf.
Then when boarding, I put the bigger backpack in the overhead, and have the smaller one at my feet.
I have much more legroom, everything I need is in it, and my backpack does not touch the floor of the plane.
I don't have to get into the overhead during the flight.
Then I do the reverse after landing.
My day bag is a nylon crossbody bag from Eddie Bauer with many zips and pockets.

For several years I've used a Patagonia Mini Messenger Bag (15" x 10" x 6.5") for my under-seat plane bag. It also doubles as my day bag for sightseeing whenever I need one.

Another bag addict here. I'm currently bringing a Tom Bihn Brakn Bag backpack (carry on) and Tom Bihn Co-pilot (personal item) for most trips. The Co-pilot is my city bag and functions as a purse than can also hold a raincoat and camera with a small lens. The backpack is for rural hiking days when I want on my person a couple liters of water, assorted snacks, a few clothing layers if needed, a first aid kit, and the Spousal Unit's overflow camera lenses.

My plane bag and my daybag are two totally different bags.
I use a Kipling Sherpa on the plane as my "personal Item" with all the things you mentioned as needed to access while on the plane. Plus it has everything you don't check in such as cash, jewelry, medication, Kindle, accordion file with all my travel docs, etc.
Inside of that bag is my smallish "daybag" which is just whatever lightweight bag I picked upat Marshalls (usually a Kipling or something like that). That bag is packed as if I am already walking around Europe because when we land, I take this bag out and it is now my purse and has been prepacked back at home with a small wallet with Euros, an envelope with my lodging, it may be the actual reservation or a card with the address written on it that i can hand to the taxi driver, Sunglasses, chap stick (also a chap stick in my carry on, can never have enough).
That Sherpa bag has a pocket to slide over the handle of my luggage and is tougher than anything. It is The perfect bag with accessible pockets on the outside in addition to a large outside pocket that runs the length of the bag.