Dustin's point on hydration is as important in my mind as getting over the jet lag induced exhaustion of flying. I don't know how many days it takes to fully hydrate after a long flight, but it must be several. The stress on the body when racing is very different to a training run, and time is needed to recover.
I usually pull on the trainers immediately after a 9 hour flight to the USA on landing and find it a great pick me up. But experiences this year of racing 13 miles two days after landing, and running a 19 miler long training run the day after flying to Alaska were both very uncomfortable.