By Foo Yun Chee

BRUSSELS (Reuters) - Lufthansa , United Airlines and Air Canada are set to win approval from the European Union's competition regulator for their transatlantic tie-up with their offer to give up airport slots, a person familiar with the matter said on Wednesday.

The three airlines last year proposed giving up landing and take-off slots at Frankfurt and New York's airports following a three-year investigation by the European Commission into their revenue-sharing, pricing and capacity pacts.

The EU antitrust authority sought feedback from rivals and third parties in December last year.

"The Commission is likely to accept the airlines' proposal with some fine tuning," said the person who declined to be named because of the sensitivity of the matter.

Regulatory approval means the airlines will not be found guilty of anti-trust infringement and will not face fines which could reach 10 percent of a company's global revenues.

The Commission spokesman for competition policy could not immediately be reached for comment.

The three carriers are all members of the Star Alliance of airlines, the biggest such marketing group with 27 members accounting for a quarter of global airline capacity.

Such alliances were set up in the 1990s to enable airlines to extend their apparent networks without having to overcome the industry's peculiar restrictions on international mergers.

This would be the second airline network cleared by the Commission. It approved a tighter transatlantic tie-up between British Airways , American Airlines and Iberia in July 2010. All three are members of the broader oneworld alliance.

The EU watchdog is also currently investigating a transatlantic joint venture between Air France-KLM , Alitalia and Delta Airlines .

(Reporting by Foo Yun Chee; Editing by Greg Mahlich)