Sept 24 (Reuters) - U.S. Transportation Secretary Sean

Duffy on Wednesday warned European governments against imposing

unilateral restrictions on transatlantic travel, saying

Washington is prepared to enforce international agreements - a

stance underscored by recent action taken against Mexico over

similar concerns.

"We're seeing more airports get in the game of trying to

restrict air traffic, which is contrary to the agreements that

we have with them," Duffy told Reuters from Montreal where he is

attending an international aviation meeting, citing concerns

about Amsterdam, Lisbon and Dublin.

"It's important for commerce, for trade, for the movement of

people in business, that we keep these flights open," Duffy

said, questioning the validity of noise data to justify flight

cuts.

Duffy in July ordered Mexican carriers to file U.S. flight

schedules and could disapprove flight requests from Mexico if

the government failed to address U.S. concerns. Earlier this

month, he ordered Delta Air Lines ( DAL ) and Aeromexico to

unwind a joint venture by January 1.

U.S. airlines have raised concerns about noise reduction

flight caps at Amsterdam Schiphol airport as well as a passenger

cap at Dublin airport that is on hold pending a legal challenge.

A Dutch court last year ordered the government to do more to cut

noise pollution. JetBlue Airways ( JBLU ) last month told USDOT

that "it is clear that an access problem exists for U.S.

carriers in Lisbon" and warned it could pursue legal action for

access.

Duffy said the administration's actions on Mexico were also

aimed at Europe. "I think Mexico is a sign that we're not going

to take that," Duffy said. "We're not at a place where we need

to apply pressure."

Duffy said the requirement that Mexico file flight schedules

"is a sign that we are willing to take additional action if they

don't come into compliance with our open skies agreement." Asked

about Delta's criticism of the decision, he said he understood

the carrier's position on the Mexico JV but said it will

probably be happy that "we are standing up for the agreements

that we have globally."