Narita airport tightened security procedures Sunday at the request of the United States, where a terror attack on a flight from Amsterdam to Detroit was foiled just before landing.
Despite being jammed with travelers at the start of the yearend holidays, airlines operating flights to the U.S. are now using tougher screening measures.
Japan Airlines and All Nippon Airways increased body checks at boarding gates, a step usually applied to just a fraction of all passengers.
They are also opening and examining all carry-on items during boarding.
The operator of the airport also asked passengers to start boarding earlier.
"I came earlier than usual because I read a newspaper article that said security would be tightened," said Katsunori Sakai, a 57-year-old dentist from Fuchu in western Tokyo going to Las Vegas with his family. "It can't be avoided for safety's sake."
A 73-year-old woman from Wako, Saitama Prefecture, head to the U.S. to meet her son said she was shocked.
"I was surprised with the tight security," she said.
A Nigerian man claiming links to the al-Qaida terrorist network set off a small explosive device aboard a Delta-Northwest Airlines flight to Detroit on Friday. The plane, which was carrying 278 passengers, landed safely.
In the wake of the attack, the U.S. Transport Security Administration asked JAL and ANA to closely inspect all passengers boarding planes to the U.S. and to conduct more body searches. The Japanese transportation ministry has instructed airlines to conduct full security checks on passengers for all flights, domestic or international.
At Japanese airports, travelers must pass through metal detectors but are not necessarily body searched.