The 22" REI Stratocruiser is a soft-sided two-wheeled carry-on bag with structured side walls and a detachable daypack. One of the larger pieces we reviewed, this carry-on held a LOT of stuff and measured 22 x 14 x 9 (main bag only). On the other hand, our testers aren't entirely convinced yet that the carry-on plus detachable daypack idea is totally worth it, but if it's something you are interested in springing for, then this bag is your most affordable option. Please check out our buying advice guide: How to Choose Carry-On Luggage and The Best Carry-On Luggage Review for a full discussion of the pros and cons of the detachable daypack.
With the REI Stratocruiser, it's easy leave the detachable daypack at home and solely use the main pack, but if you do opt to use the daypack as your personal item, you can easily clip it onto the main pack at three points using plastic buckles. Because it is easy for your to clip on and off, we want to take a minute here to point out that it would also be easy for a pickpocket to clip it on and off. If you opt to wear this piece as a backpack with the daypack clipped onto it while you are in a crowded area, keep in mind that it is probably not wise to leave all your valuables in this daypack (and since you couldn't bring a purse as your carry-on, all your valuables are probably in that daypack). The Osprey Ozone Convertible 22 has overcome this problem by placing clips on its front shoulder straps so that you can kangaroo carry your daypack in front of you.