Sometimes. The term "economy flight syndrome" refers to a DVT ocurring when remaining seated in cramped coach seats during long flights. Although rare, this can occur in people with a high risk of dvt. The simplest preventions are calf exercises while sitting and walking periodically. In rare cases, a blood thinner can be prescribed for use prior to flying. Aspirin has not been shown to decrease DVT risk.
Possibly. As dr. Roth said, immobility is the issue. It is easier to move if you have an aisle seat and much easier to move if you aren't flying coach.
No. Only few patients.