There is a higher risk than normal of getting blood clots if you get a flight after having an abortion. In addition the person may feel a bit unwell and may be emotional after an abortion. If they absolutley had to get the flight I would advise taking aspirin, getting flight socks, ensuring they get up and move during the flight and seek medical assistance if any symptoms of a blood clot arise. They should also discuss it with their GP first and see what they advise.