Sept. 11, 2011  -- Fighter planes were scrambled, bomb squads were called, FBI command centers went on alert and police teams raced to airports today, but in the end two separate airline incidents were caused by apparently innocent bathroom breaks and a little "making out," federal officials said.

In the first incident, a pair of fighter jets were scrambled to escort an American Airlines jet into New York's JFK airport after the pilot became spooked by passengers' frequent trips to and from the restroom.

The precaution turned out to be unnecessary as federal air marshals aboard flight 34 from Los Angeles to JFK were able to resolve the situation when the passengers complied with their instructions, police officials said. The pilot then radioed that the situation was under control and the plane landed safely. Three male passengers were questioned upon arrival, but no charges were filed against them, authorities said.

The incident occurred around the same time that a second pair of fighter jets hit the skies to monitor another plane – this one a Frontier Airlines flight from Denver to Detroit – after two passengers aboard that plane were "allegedly behaving suspiciously," according to the FBI spokesperson in Denver, Dave Joly. The plane was met in the Detroit airport by law enforcement and taken to a remote area for a security screening, but no explosives were found, Joly said.

Instead, the "suspicious behavior" was two people "making out" in the bathroom mid-flight, law enforcement sources told ABC News. Three people were taken into custody for questioning, Frontier Airlines said in a statement, but no arrests have been made in that case either.

The incidents come as the nation observes the tenth anniversary of the Sept. 11, 2001, terror attacks in which four passenger planes were hijacked. Nearly 3,000 Americans perished in that attack.

ABC News' Clayton Sandell contributed to this report.

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