Venous thrombosis. If you were diagnosed with dvt, deep venous thrombosis aka ckot in leg, the concern is clot breaking loose from leg and traveling to your lung. Once diagnosed and on treatment this risk of pulmonary embolism drops. After a week, you can air travel. Stay hydrated, wear compression devices and continue your rherapy.
Maybe. If you have a blood clot, are on blood thinners and compression stockings, and your doctor feels that the situation is stable enough for you to fly, go ahead. Hopefully, you are going to do something fun wherever you land.
If anticoagulated. You may do anything your doctor permits when under anticoagulation. My feeling is that flying is ok, since clot formaiton (which has a higher likelihood when sitting for a long time) is being inhibited by the anticoagulation. Other doctors may feel otherwise, however, and you should check with your own medical provider.
Yes. If you are already receiving treatment for the blood clot and you are tolerating the treatment well, there is no reason why you cannot fly. Remember to get up and walk around every hour.
I would not. Not until treated properly.