According to Wikipedia and other source:
"Columbine II is the first plane to bear the call sign Air Force One. This designation for the U.S. Air Force aircraft carrying the incumbent president was established after an incident in 1953, when Eastern Air Lines 8610, a commercial flight, crossed paths with Air Force 8610, which was carrying President Eisenhower. Initially used informally, the designation became official in 1962."
What if disaster happen and both aircraft collided in midair, killing the President Eisenhower. Would the world change much or keep almost the same as OTL?