In the first incident, Delta Airlines Flight 1706 from Detroit to San Diego, was diverted to Albuquerque, New Mexico, deplaned and thoroughly searched after a flight attendant found a suspicious note in a lavatory.
After the search, "no suspicious devices were found," FBI spokesman Frank Fisher said in an email.
The flight was later cleared to continue on its route. Officials declined to comment on the nature of the diversion and whether it was related to the Continental flight.
In the second incident, a Chicago-bound Continental flight was diverted to St Louis after a passenger tried to open an exit door to get out of the plane.
A 34-year-old passenger from Burbank, IL, created panic in the flight, immediately after 20 minutes of take off from Houston yesterday, by walking towards the front of the cabin, saying he had to get off the plane.
He also made an attempt to open an emergency exit door but failed. There were loud screams on board as men throughout the cabin dashed toward the disturbance.
The passenger's actions forced the pilot to contact air traffic controllers. They diverted the airplane to Lambert-St. Louis International Airport and it landed safely.
The man was in police custody and was being questioned about the incident, according to authorities. The man had not been charged by so far.
None of the 160 passengers aboard the flight were injured. The flight arrived in Chicago, 1 hour and 9 minutes behind schedule.
Adding to two other mid-air security incidents, a Yemeni passenger, Rageit Almurisi, started banging on the cockpit of an American Airlines Flight going to Chicago.
The 28-year-old passenger had to be subdued by other passengers and flight attendants, who wrestled and handcuffed him, NY Daily News reported.
There were 162 passengers onboard the flight.
Rageit faces federal charges of interfering with the flight crew.
