Would this be suitable to take on a plane?
You can take pretty much ANY stroller on a plane as the baby's free luggage (if the baby's under a certain age). If it doesn't comply with the hand luggage requirements/mostly the dimensions after folding, they will take it from you when boarding and give it back when getting off the airplane.
About the dimensions of the Oyster Atom2 - they are, unfortunately, too large for the carry-on measurements of most airlines - that is why we state a No in the plane-friendliness section in the specifications under The Fold (just click on them next time). Most airlines won't accept it as hand luggage with the dimensions of 64 cm x 57 cm x 27 cm - but be sure to check the requirements for a carry on piece of luggage of your airline, maybe you'll be in luck and they'd accept it (most airlines accept only a length of under 60 cm, I'm afraid).