On June 20, 1937 a Soviet plane flew over the N pole, penetrated US airspace, and got as far a Vancouver, Washington.
The crew and airplane were quickly released into the USSR custody.
No one killed, no shots fired.
Now when we send a U2 across Soviet airspace on May 1, 1960 is the favor returned?
No. Shoot it down, imprison the pilot...
Russian bastiges.