MONTREAL/SINGAPORE (Reuters) - A U.S. push for new global standards to kickstart its fledgling supersonic jet industry is facing resistance by European nations that want tough rules on noise, according to documents and people familiar with the situation.

FILE PHOTO: The Aerion AS2, the world's first supersonic business jet, being developed by Lockheed Martin Corp partnering with plane maker Aerion Corp of Reno, Nevada, is shown in this handout photo illustration released December 15, 2017. Aerion Corporation/Handout via REUTERS/File Photo

Fifteen years after Concorde’s last flight, U.S. regulators are weighing rule changes to allow testing of early-stage supersonic jets, amid plans for American-made business and small passenger jets due in service by the mid-2020s. But the new industry could face delays at the United Nations aviation agency where the United States and European countries - including France, Germany and Britain - are squaring off over new noise rules needed for the jets to fly, five sources told Reuters, speaking about confidential talks on condition of anonymity.

The previously unreported dispute follows a 1990s clash on noise standards, when the European Union wanted to ban noisy older U.S.-made jets like the Boeing 727 from its airports and Washington threatened to retaliate by banning the Anglo-French Concorde.

This latest round pits U.S. ambitions for an American-led revival of supersonic jets by start-ups Aerion Supersonic, Boom Supersonic and Spike Aerospace against European fears of disruptive noise from the planes. Aerion, backed by Lockheed Martin Corp and GE, is considered by industry sources as the most advanced of the supersonic projects.

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Boom will be making its first appearance at the Farnborough Airshow next week as it looks to cement the revival of the supersonic industry, which is struggling to design jets that meet current subsonic noise standards due to engine constraints.

“The politics are that Europe is way more worried about noise (around airports),” said an industry source familiar with the matter. “Europe has a problem but they have no reason to solve (it) because they have no industry pushing for this.”

That’s a reversal of disputes which delayed the beginning of Concorde’s transatlantic services in the 1970s, as first the U.S. Congress and then the New York Port Authority banned it due to noise. The Federal Aviation Administration (FAA) has banned supersonic flights over U.S. land since 1973.

For now, the new jets plan to stick to over-water routes, though the FAA will eventually decide whether to allow overland flights after analyzing data from NASA in a study by 2025.

GLOBAL STANDARDS

Both Boeing and Airbus have mapped out futuristic visions for ultra-fast air travel.

But since the demise of Boeing’s planned near-supersonic Sonic Cruiser in 2002, the world’s two largest planemakers have focused on slower, fuel-efficient planes that allow airlines to lower ticket prices.

Now, U.S. startups are working to develop quieter and more fuel-efficient supersonic planes than Concorde, aimed at business travelers. They claim these can be economically viable with the right engine. They also pledge to dampen the famous sonic boom which depressed Concorde’s sales and restricted its operations until it was grounded for economic reasons in 2003.

The United Nations’ Montreal-based International Civil Aviation Organization (ICAO), which sets many global standards, has started looking at supersonic jets by seeking technical information from planemakers.

ICAO will then be in a better position to assess options for standards on noise and emissions, and “how long the process should take,” a spokesman said.

While the aviation industry prefers to have common international rules developed through ICAO, the FAA said on Thursday it is also looking at domestic noise requirements.

“In the event of a delay in the adoption of international standards, the FAA will need to establish noise regulations for domestic certification,” it said.

The European countries think current noise limits should be used as “guidelines” for developing landing and take-off rules, according to a document presented to a recent ICAO committee meeting and seen by Reuters.

The United States, echoing industry’s demand, has called for new standards that reflect “fundamental differences” between subsonic and supersonic jets, according to a second document.

“You can’t try to shoehorn a supersonic aircraft into a subsonic standard,” said Mike Hinderberger, Aerion senior vice president of aircraft development at an industry conference last month.

Aerion declined to comment further.

It’s not yet clear how other countries see supersonics or whether ICAO could craft a compromise.

CHICKEN AND EGG PROBLEM

Lengthy delays by ICAO would likely force planemakers to hold off, or risk investing millions in a design that “no one will certify,” said a U.S. industry source.

“It’s a chicken and egg argument,” added the first industry source. “How can you bring a plane to market if you don’t have the standards to meet?”

Noise standards “need to be defined as soon as practicable so that manufacturers have certainty,” said the FAA. “The sooner the agencies finalize guidelines and standards, the sooner we can ensure our design meets those requirements,” said Vik Kachoria, CEO of Boston-based Spike Aerospace, which hopes to select an engine for its jet early next year.

The European nations, however, are seeking robust data. In a separate document on emissions, they said they do not expect new standards “before 2025 or later” because of insufficient data.

Boom CEO Blake Scholl said he had faith that the international community would ultimate reach agreement on supersonic noise standards, due in part to customer demand to get to destinations faster.

“Supersonic flight will be a critical driver of human progress, and we believe Europe’s citizens will embrace it,” he said. “We know noise is a sensitive issue, and we are designing with that in mind.”