The latest incident happened late Sunday on a flight from Chicago to San Francisco. Passengers helped subdue a man whom authorities say was pounding on the cockpit door during Americans Airlines Flight 1561.
On another flight from Houston to Chicago, a man tried to open a plane exit door mid-air.
Both incidents are making travelers nervous.
After banging on the cockpit door and shouting during the Chicago-to-San Francisco flight, Rageit Almurisi, 28, was pinned down by two flight attendants and two Air Marshals. The suspect -- a California man who carries a Yemen passport -- was handcuffed and now faces federal charges of interfering with a flight.
The flight landed safely in San Francisco Sunday night.
"The flight attendant called for some help. Some passengers from the first-class section, along with other flight attendants, assisted the flight attendant. Some flexible,plastic handcuffs were used by the flight attendants to secure the hands of that passenger," said Sgt. Michael Rodriguez of the San Francisco Police Dept. "That passenger was then placed into a first-class seat where he was held until the flight arrived at SFO."
Andrew Wai snapped photographs showing the ordeal. Passengers could be seen staring at the man as he was subdued.
"Passengers all around me were crying. Flight attendants were trying to sooth different passengers. We all were looking at our lives flashing before our eyes," said Wai.
Hours earlier, another scare in the sky occurred on a Continental Airlines flight from Houston to Chicago. Flight 546 was diverted to St. Louis after Reynel Alcaide, a 34-year-old passenger from southwest suburban Burbank, Ill., attempted to open a plane exit door. It took several passengers and attempts to take down the man who was described as a husky bull.
"There was this commotion. The flight attendant came on and said, 'we are being diverted to St. Louis because there's been an incident.'...then we saw the men moving quickly to the front," said Sonia Cunningham, passenger.
Chicago native Tony Harris says he used his martial arts skills to hold the suspect down.
"I asked him, 'What in the hell were you doing? What were you thinking?' He said, 'Well, it's Mother's Day,'" said Harris. "What I did was I jumped on him, I wrapped my legs around him, I put my 210 pounds of weight on his neck."
"He was up there is a flash, I have to tell you. He had the guy in a choke hold. He broke his shoe getting it done. And I also have to say Americans aren't going down like that anymore. The men were all up and out in a minute getting him subdued," said Cunninham.
Alcaide has been charged with causing a disruption on board.
Harris, who ended up sitting with Alcaide until the flight landed, suspected the man may have been suicidal. Federal authorities will only say the incident was not a case of terrorism and they are still investigating.
Passengers at Chicago's O'Hare Airport said they were on alert Monday.
"I just hope that's not going to happened this week and that they have a lock down on everything," Julie Knorowski told ABC7 Chicago.
"I'm a little worried, concerned. Is this something to lose sleep over? Nah, but very concerned," said Akanni Salako.
No one was hurt on either of the flights. Overall, passengers say the incidents won't stop them from flying, but they will be more aware.