Adds details throughout from the statement on route cuts, background, Airbus delivery

NEW DELHI, Feb 4 (Reuters) - India's IndiGo INGL.NS said on Wednesday it would suspend long-haul flights to Copenhagen and trim some services between Delhi and Britain, citing operational constraints from airspace closures linked to geopolitical tensions and airport congestion.

It is the second major Indian airline to scale back overseas operations after Air India, which has suspended some U.S. routes because Pakistan has banned Indian carriers from its airspace.

IndiGo did not specify the geopolitical issues it faces, but airspace closures in the Middle East have disrupted airline schedules in recent months. The restrictions and congestion at airports in India and abroad have significantly increased flight times for its leased Boeing BA.N Dreamliner jets, it said.

The airline said it was taking immediate steps to restore reliability in its widebody operations. India's largest carrier faced criticism in December for poor pilot roster planning that triggered large numbers of domestic flight cancellations.

IndiGo will suspend Copenhagen flights from February 17, just months after launching the route in October. It will also cut Delhi–Manchester services to four flights a week from February 7 and to three from February 19, while reducing Delhi–London Heathrow operations to four flights a week from five.

"IndiGo will continue monitoring these external developments and flexibly scale its network up or down to align with evolving conditions," it said.

The airline has been using Dreamliner aircraft leased from Norse Atlantic Airways on the routes. IndiGo, one of Airbus' AIR.PA largest customers, expects its first A350 widebodies in early 2028, slipping from a previous 2027 target.

(Reporting by Hritam Mukherjee in Bengaluru and Abhijith Ganapavaram in New Delhi. Editing by Mrigank Dhaniwala and Mark Potter)

((mailto: hritam.mukherjee@thomsonreuters.com; @MukherjeeHritam;))