Hi..I Have A Very Large Painful Hematoma On My Left

Hi..I have a very large painful hematoma on my left leg in the area of the knee after a car accident almost 5 months ago lateral side
It is extremely painful.My dr's have said it's okay to fly and have to inject an anti-coagulant before flying there and back.I will also book a sest with extra leg ròom so I can stretch my leg.Is there any danger to me