Rick's Classic Back Pack - Depth Adjustable?

Google IATA cabin OK or even IATA carry on. That should get you quite a few hits.

Also “international carry on”.

The Rick bag should work with the cinch straps but you may still get bulging in the middle. The best way to counteract that is packing cubes.
And of course, underpack!

Empty, the RS bag lays flat. As long as you don't fill it to more than 20 cm you will be fine.

As Cindy mentioned, there are numerous soft sided convertible bags that would work.

The airlines don't sit the bag on a table and let it assume it's free shape and then measure the height and width. They have you put it in a "sizing frame" with sides that are 20 cm (8-7/8") apart. As long as the cross-sectional area is less then 124 sq inches (2 sq inches less than 14 x 9) it should fit in the frame without exceeding the 15¾" width.

Unless filled to bursting, soft convertible bags are very flexible. Unless you are going to take everything you can possibly image you will need and stuff the bag so you can hardly close the zipper, it should easily fit in the sizing frame. For many years, I took a RS bag (ca. 2000) to Europe. It was hardly ever checked for size, but when it was, it passed easily.

Although the max thickness is 8-7/8" vs the 9" of the RS bag, the Air Italy width limit is 15¾ instead of 14". Those limits give you almost exactly the same cross-section and perimeter as the RS bag dimensions.

One way we’ve gotten around this is thoughtful packing including RS compression bags (see the RS Store for some good quality ones); pack light (you likely can buy toiletries and more clothes at destination); assume you can purchase other needed items upon arrival; take ‘the minimum needed to get you there’. If country you are visiting has reasonable postage prices, you can ship home anything you cannot fit into suitcases prior to leaving.
Upon arrival at destination, we use shopping for food and toiletries as our excuse to walk off jet lag. Or, in one case, I needed a new puffer coat and sneakers. Was fun to shop for those in UK.

With a little forethought and ingenuity you can do this :)

Thanks! Puts my mind at ease over the prospect of giving them an extra $210 for two small bags.

Anyone know if the convertible carry on is also a good option for light packing-no checking on European airlines? I noticed that one is on sale...

If you can keep the size of the bag to that 20cm and the weight under 8 kg, you will be good for most European airlines except a few that only allow personal size items. (Example--Ryanair)

But all airlines are different. You have to check each one.

An alternative is the Ebags Weekender Convertible Junior, which is slightly smaller at 19" in length. The downside is that it's a bit heavier than the RS convertible backpack, so strategic packing is key. The previous post about checking each airline's regs is on point, as the European carriers generally tend to be more strict about their size and weight restrictions.

I have bought one of Rick Steve's Classic Backpacks for a 43 day trip through several countries. Does everyone find this bag comfortable to use even though it is as wide at the the top as at the bottom? I am planning on packing very light. Thank You.

I have bought one of Rick Steve's Classic Backpacks for a 43 day trip through several countries. Does everyone find this bag comfortable to use even though it is as wide at the the top as at the bottom? I am planning on packing very light. Thank You. <<

Most travel packs that are less than, say, $250 are basically soft sided rectangular cubes with some straps. A more sophisticated travel pack, something that comes from a sporting goods company such as Osprey or TNF, may have a very nice suspension harness and a more ergonomic shape. That’s usually because those packs will be intended to carry heavy loads long distances over rough terrain. If you need a great harness, a functioning hip belt, and ergo shape, you should probably be looking at different bags. There’s a fun if confusing shopping experience.

Many of us who use simple (inexpensive, even cheap) travel bags don’t need that kind of design sophistication. I don’t have any experience with the RS bags but my PacSafe is similar; it’s just a soft rectangular bag with some shoulder straps and a minimum hip belt.