Flight crews and air marshals say Middle Eastern men are staking out airports, probing security measures and conducting test runs aboard airplanes for a terrorist attack.
At least two midflight incidents have involved numerous men of Middle Eastern descent behaving in what one pilot called "stereotypical" behavior of an organized attempt to attack a plane.
"No doubt these are dry runs for a terrorist attack," an air marshal said.
Pilots and air marshals who asked to remain anonymous told The Washington Times that surveillance by terrorists is rampant, using different probing methods.
"It's happening, and it's a sad state of affairs," a pilot said.
A June 29 incident aboard Northwest Airlines Flight 327 from Detroit to Los Angeles is similar to a Feb. 15 incident on American Airlines Flight 1732 from San Juan, Puerto Rico, to New York's John F. Kennedy Airport.
The Northwest flight involved 14 Syrian men and the American Airlines flight involved six men of Middle Eastern descent.
"I've never been in a situation where I have felt that afraid," said Annie Jacobsen, a business and finance feature writer for the online magazine Women's Wall Street who was aboard the Northwest flight.
The men were seated throughout the plane pretending to be strangers. Once airborne, they began congregating in groups of two or three, stood nearly the entire flight, and consecutively filed in and out of bathrooms at different intervals, raising concern among passengers and flight attendants, Mrs. Jacobsen said.
One man took a McDonald's bag into the bathroom, then passed it off to another passenger upon returning to his seat. When the pilot announced the plane was cleared for landing and to fasten seat belts, seven men jumped up in unison and went to different bathrooms.
Her account was confirmed by David Adams, spokesman for the U.S. Immigration and Customs Enforcement's Federal Air Marshal Service (FAMS), who said officers were on board and checked the bathrooms several times during the flight, but nothing was found.
"The FAMS never broke their cover, but monitored" the activity, Mr. Adams said. "Given the facts, they had no legal basis to take an enforcement action. But there was enough of a suspicious nature for the FAMS, passengers and crew to take notice."
A January FBI memo says suicide terrorists are plotting to hijack trans-Atlantic planes by smuggling "ready-to-build" bomb kits past airport security, and later assembling the explosives in aircraft bathrooms.
On many overseas flights, airlines have issued rules prohibiting loitering near the lavatory.
"After seeing 14 Middle Eastern men board separately (six together and eight individually) and then act as a group, watching their unusual glances, observing their bizarre bathroom activities, watching them congregate in small groups, knowing that the flight attendants and the pilots were seriously concerned and now knowing that federal air marshals were on board, I was officially terrified," Mrs. Jacobsen said.
"One by one, they went into the two lavatories, each spending about four minutes inside. Right in front of us, two men stood up against the emergency exit door, waiting for the lavatory to become available. The men spoke in Arabic among themselves ... one of the men took his camera into the lavatory. Another took his cell phone. Again, no one approached the men. Not one of the flight attendants asked them to sit down."
In an interview yesterday with The Washington Times, Mrs. Jacobsen said she was surprised to learn afterward that flight attendants are not trained to handle terrorist attacks or the situation that happened on her flight.
"I absolutely empathize with the flight attendants. They are acting with no clear protocol," she said.
Other passengers were distraught and one woman was even crying as the events unfolded.
The plane was met by officials from the FBI, Los Angeles Police Department, Federal Air Marshal Service and Transportation Security Administration. The Syrians, who were traveling on one-way tickets, were taken into custody.
The men, who were not on terrorist watch lists, were released, although their information and fingerprints were added to a database. The group had been hired as musicians to play at a casino, and the booking, hotel accommodations and return flight to New York from Long Beach, Calif., also checked out, Mr. Adams said.
"We don't know if it was a dry run, that's why we are working together with intelligence and investigative agencies to help protect the homeland," he said.
Mrs. Jacobsen, however, is skeptical the 14 passengers were innocent musicians.
"If 19 terrorists can learn to fly airplanes into buildings, couldn't 14 terrorists learn to play instruments?" she asked in the article.
The pilot confirmed Mrs. Jacobsen's experience was "terribly alike" what flight attendants reported on the San Juan flight.
He said there is "widespread knowledge" among crew members these probes are taking place.
A Middle Eastern passenger attempted to videotape out the window as the plane taxied on takeoff and, when told by a flight attendant it was not permitted, "gave her a mean look and stopped taping," said a written report of the San Juan incident by a flight attendant.
The group of six men sat near one another, pretended to be strangers, but after careful observation from flight attendants, it was apparent "all six knew each other," the report said.
"They were very careful when we were in their area to seem separate and pretended to be sleeping, but when we were out of the twilight area, they were watching and communicating," the report said.
The men made several trips to the bathroom and congregated in that area, and were told at least twice by a flight attendant to return to their seats. The suspicious behavior was relayed to airline officials in midflight and additional background checks were conducted.
A second pilot said that, on one of his recent flights, an air marshal forced his way into the lavatory at the front of his plane after a man of Middle Eastern descent locked himself in for a long period.
The marshal found the mirror had been removed and the man was attempting to break through the wall. The cockpit was on the other side.
The second pilot said terrorists are "absolutely" testing security.
"There is a great degree of concern in the airline industry that not only are these dry runs for a terrorist attack, but that there is absolutely no defense capabilities on a vast majority of airlines," the second pilot said.
Dawn Deeks, spokeswoman for the Association of Flight Attendants, said there is no "central clearinghouse" for them to learn of suspicious incidents, and flight crews are not told how issues are resolved.
She said a flight attendant reported that a passenger was using a telephoto lens to take sequential photos of the cockpit door.
The passenger was stopped, and the incident, which happened two months ago, was reported to officials. But when the attendant checked back last week on the outcome, she was told her report had been lost.
Recent incidents at the Minneapolis-St. Paul international airport have also alarmed flight crews. Earlier this month, a passenger from Syria was taken into custody while carrying anti-American materials and a note suggesting he intended to commit a public suicide.
A third pilot reported watching a man of Middle Eastern descent at the same airport using binoculars to get airplane tail numbers and writing the numbers in a notebook to correspond with flight numbers.
"It's a probe. They are probing us," said a second air marshal, who confirmed that Middle Eastern men try to flush out marshals by rushing the cockpit and stopping suddenly.