Yes, I had just sent the chinook out to get to the presumed crash site.
I have saved the game after the F-16 reached the new hangar. After restarting and reloading the game I still cannot build the MIG in the old base. (I would attach the save game but I get a 404 error when I click on attachments in the forums. i could send it per mail though if you PM me with your address.)
In step 1) I built a base with 1 Hangar, Living Quarters, Medical Center, Storeroom, Radar. When the Storeroom was completed I started building a second Hangar and a Garage. The transit took place after Hangar 1 was finished. Hangar 2 is still taking 8 days. So maybe that unfinished hangar could be the cause?