In that incident, in the US state of Missouri, the pilot managed to eject safely.
However, several defects were found in some of F-15s.
Extensive search
More than 60 US coast guard personnel were involved in Wednesday's search using helicopters, ships and jets, a coast guard spokesman said.
A rescue jet located one pilot and radioed the location to a fishing vessel, which picked him up and then passed him on to a helicopter, James Harless, a coast guard petty officer, told AP. 
The second pilot was found after the first told the coast guard of his approximate location.
The pilots were then taken to the Eglin base hospital. Their condition is not yet known.
The weather in the area at the time of the incident was reportedly calm, officials said.
Air force officials are investigating the incident.