Carry On vs. Checking

Unfortunately there are no hard rules on this question. It depends on gate personal and their perception of the needs for that flight. Our experience is that US carriers tend to be a little looser while European airlines tend to be more strict.

Depends on the carrier and departure airport. In all of our years of traveling we have had only one airline actually weigh our carryon bag. That was Air Tahiti Nui from Papeete to LAX. They did not weigh our carryon for the outgoing flight from LAX to Papeete. The carryon baggage size guideline for Aer Lingus is 21.5 in x 15.5 in x 9.5 in, while United is 9 inches x 14 inches x 22 inches. I do not believe that you will have a problem. Just don't overload your backpack!

The Aer Lingus personnel will go with their standards for suitcases. Be ready to have to check it - meds, anything essential, etc. already in your backpack. For instance, when I fly Delta and it switches on the last flight to a KLM flight, I have to follow their sizes.

Each airline will enforce their own standards. Airlines usually pay more attention to sizes if the flight is full.

Airlines seem to be seeking to recoup some of their losses from the past couple of years by charging more for checked bags and by being stricter about sizes.

When booking flights and having to use different airlines - follow the rules of the most restrictive airline. Or, just be willing to pay some luggage fees. I understand wanting to avoid luggage fees. But, in the grand scheme of traveling, paying a few fees for things like a cab ride (over public transportation), luggage fees, laundry fees to have someone do your laundry - these fees if reasonable can be worth it to make traveling easier.

We have been “stuck” for luggage a couple of times over discrepancies by different airlines. All one can do is shrug the shoulders, pay the fee, and move on. So, I now check the baggage policy of all airline carriers and determine the cheapest way for my family to pack. (Example: if one larger checked bag is cheaper than 2 carry-on bags (looking at you Frontier Airline), then that’s what we do.). I also double check a few days before flying. We have been “stuck” because an airline changed its baggage policy after we booked the flight. We received no advance notification from the airline. The baggage policy changed just a few days before our flight.

Our experience coming back from Heathrow last Wednesday only emphasizes the need for carry on. Make sure it will fit all airline standards, downsizing if you need to.

Thanks everyone. I suspected that Aer Lingus rules would apply. As much as I would like to be able to carry on we can’t manage such a long trip with even smaller bags. We will have to gate check our bags for the flight from SMF - SFO, so we will just check our bags at SMF and they will be checked through to Dublin. We have a long layover at SFO so there hopefully won’t be any problem with our bags arriving with us.

Andrea, I would not jump to that conclusion just yet. Consider all of the following:

Our luggage is considered carry on size for United, but is slightly too big for Aer Lingus.

Your fate may be determined by your honest definition of "slightly", and also the following factors beyond your control...

• The mood and whims of the Aer Lingus gate staff (if they've been having a bad day, the more likely you will too)
• How full your flight is (the more full, the less leeway you get)
• Your class of service (flying business class? they'll cut you a lot more slack; basic economy? expect no sympathy)
• Got any elite status? (if yes, they're more likely to be lenient)
• How your luggage looks  (if it's obviously, grossly oversize, don't expect to get a pass)
• Are you feeling lucky? (well, there's the old "Luck of the Irish"...)

Exactly how "slightly" oversize is it? Less than an inch, you have a good chance they won't care. Several inches in multiple dimensions? More danger.

That said, I have found the staff at Aer Lingus to be extremely friendly, and eager to please (this was pre-pandemic, pre-meltdowns, they might not be quite so gregarious now).

One other thing you have going for you: there are two potential places where your "slightly oversize" bags may get flagged and potentially rejected: at the check-in counter, and at the gate(s). Since you are connecting in SFO, your carry-ons won't get scrutiny at the Aer Lingus check-in counter (they'll get a less-thorough look by the United staff in Sacramento). You'll only have to pass muster at the gate in SFO, and you'll have the advantage of being a transit passenger, so they'll know (if they care to look) that you came off a partner flight. That may result in less scrutiny or looser enforcement.

But the bottom line is: there's no way to know for sure. You should prepare for the worst and hope for the best. Be prepared to pull what you need most and have them gate-check your backpacks.

Pro Tip/Sneaky Trick: if you can manage to leave some room in your pack, even most slightly oversize bags can be squeezed into a physical "sizer" box. You could (and should) even remove SOME of your stuff from your backpack, move it to a small day-pack as you go through the gate check. Your big backpack (now empty enough to squeeze down to legal size) = your "carry on", and the smaller day-pack (needs to be pretty small) = your "personal item". Once you're past the gate dragons, you can re-combine your stuff as needed. Get creative and you can usually make this work. Don't ask me how I know...

Good luck and have fun in beautiful Ireland!

Don't count on status helping-In fall of 2019, Air France made my diamond million-miler Delta flyer check the carryon Delta gave him when he reached a million miles-and it's entirely possible that he was flying business class.

I’ve taken a carry on on air lingus that was a couple inches longer than their dimensions and didn’t have an issue. If it’s only slightly off, it’s doubtful they will flag it. It’s a risk but I would just try to carry it on and check it at the gate if they make you

If you are checking bags ... do the math. It may be cheaper to check one larger bag than 2 carry-on bags. (Provided you can manage a larger bag on trains, etc.. - I can.). Then, have an underseat bag at no charge. You can put “overflow” items due to weight or volume in the underseat bag.
Here’s a couple of good underseat bags - RS Appenzell backpack, Patagonia lightweight tote pack, RS packable duffle - cylinder shaped one, some other bag like a zip top LL Bean tote. RedOxx has a couple, but they are heavy duty and costly. Tom Bihn copilot or cadet.
I understand some airlines are restrictive about underseat bag (personal item) with regard to weight and size.

We each get a free checked bag. We need to keep them carry on sized because we will have 4 suitcases and 4 personal sized backpacks (4 people) that will have to fit in the back of the compact SUV’s we are renting in Ireland and Scotland.

I had the same issue flying to Germany where one leg was with Air France, which had stricter luggage requirements than Delta. I ultimately decided to check the bag - I don't like leaving things like that to luck.

Mardee, I feel the same. I’ll bring a change of clothes and other necessities on the plane. We have 3 nights in Dublin, so if by chance our luggage is delayed we will be there for awhile. We have a 9 hour layover at SFO since they have changed our flight from Sacramento twice. We probably have to gate check our bag from Sacramento anyway.

Andrea, if you have an iPhone (or anyone in your party does), you may want to buy an AirTag to slip into your checked luggage (for peace of mind). I bought a couple before my trip and put one in my checked suitcase. It was comforting to know that my bag was making it to all the right airports and places it was supposed to be. :)

Mardee, that’s the plan. We have to check our bags on a Ryanair and an EasyJet flight later in the trip.

We flew PDX to SFO, then SFO to Dublin on Aer Lingus about 3 weeks ago. The Aer Lingus gate agents appeared to be disorganized, and did not scrutinize carry on luggage. Their focus was checking passports and your boarding pass. On a side note, be careful as there is a Covid surge going on in Ireland, and we had to quarantine over there for 5 days after testing positive. According to the taxi driver who took us to the airport, “nobody wants to talk about it.” Safe travels.

I looked, unless I read it wrong  Aer Lingus allows a little wider and a little deeper bag, but 1/2" shorter. You can't just squish a backpack for a half inch?

United 9 x 14 x 22 no weight limit
Aer Lingus 9.5 x 15.5 x 21.5 10kg weight limit

My suitcase is 22x13x9. My husband’s is slightly wider. The Aer Lingus personal bag allowance is pretty small compared to the domestic carriers. We use backpacks for our personal bags. Because we have a 9 hour layover (we hope to leave the airport during that time to visit with relatives that will pick us up and drop us off, but it’s possible we will just hang out in the United Club at the airport) I would rather not have to drag our bags around. I plan to have a small packable tote bag with a change of clothes for each of us and any other necessities, just in case our bags are delayed.

You are correct their personal item max size is tiny.