I have home-made ripstop sleeves for all my umbrella strollers, including my Mac. The sleeve leaves two wheels and the handles exposed, so I can pull it behind me down the jetway. Easy-peasy to do if you sew.
Just cut a large rectangle of 45" ripstop wide enough to wrap around the widest point of the stroller's circumference when folded, plus 4 inches for hem overlap. Hem both sides 1" and use wide sew-on velcro to put a line of squares down these edges to fasten in an overlap.
Use hem tape to make a casing at the top and bottom edge and fill the casings with 1" elastic tight enough to fit snugly around the stroller circumference at the point where it will rest (Between the wheels on the bottom, and just above the hood on the top.) Set a heavy-duty snap into the ends of the elastic sections (the rest of that edge overlap seals with the velcro, but you'll need strong snaps to hold the elastic closed.)
For a useful touch, add a securely-sewn "handle" of webbing or folded/sewn fabric on the flat part of the outside about 12" from the top edge. This is not for carrying the stroller; that really would not hold. The function of this is to give the airline a nice secure place to attach the gate-check and baggage barcode tags. (Write or embroider your name on the sleeve, and also make sure that you have a luggage tag on the frame of the stroller itself; just in case some busybody takes the cover off somehow.)
These covers work just wonderfully (mine are VERY brightly colored), and it is nice to be able to bag it up at the gate while waiting and just pull it down the jetway with one hand. My Peg Pliko was a bit harder to make one for because it stands on end, and I had to add a heavy vinyl panel to keep it from wearing too much there.
