I think I've done this -can't remember if I have an Oyster or another model. My friend bought a couple of Samsonites off craigslist, and I bought the smaller one off him. Initially when I tried it, I thought I made a huge mistake, and that is wouldn't work. However assuming you have the smaller Samsonite I have, you might have to remove* the stem and rear derailleur from the frame which aren't immediately obvious but I needed to do to get it to fit. Even then, it was a tight squeeze.
Forgot to say, I do know my suitcase is completely airline legal size wise since I checked it out -if that helps -and my friend's suitcase is maybe an inch too wide but not noticeable if you were checking it in. I have the front suspension model -and wouldn't the no suspension model be easier since it is smaller?
*assuming you've done the obvious -removed the wheels, take off saddle and seatpost, pedals etc