If you have complications you won't be getting on a plane - you'd probably be in the hospital. Just in case you don't know this, ask for a wheel chair when you make your reservations or when you get to the airport. That will expedite your processing through check-in lines. You will also be able to get on the plane first and settle in.
You don't need to do 'vigorous' leg
exercises on the plane. There are very simple methods for keeping your blood moving. And I'm sure you won't want alcohol right after having had surgery. You can also purchase compression stockings which will add another layer of prevention. I've had 3 bouts of pulmonary emboli in both lungs - not from flying - from something mysterious that they can't figure out. If this is a major concern, talk with your doctor and s/he may prescribe blood thinners. Aspirin can be used but it may not be strong enough and it may contraindicated because it is an NSAID which has been found to cause or promote pouchitis. But maybe the NSAID use isn't a problem for a 1-time use on the plane. But, of course, ask your doctor.
A two hour flight is fairly short and it shouldn't be a problem at all. If something occurs while you're in the air and it's a dire situation, I'm sure the plane would land and get you medical assistance. But even a blockage shouldn't be a concern because most blockages resolve and if they don't right away, a two hour flight with a blockage would not be life-threatening.
I'm glad you've finally made the appointment and you're getting the surgery. Hopefully you'll experience no road bumps and you'll be out living a full life very soon after your surgery. Even with an ostomy, there will be nothing you can't do. Weight lifting. Martial arts. Biking. Diving. Climbing. There are products for protecting your ostomy while in water or engaging in physical sports.
kathy