William Shatner -- Jets Back to L.A ... Mum About Leonard Nimoy's Funeral

William Shatner made a surprising return to Los Angeles Sunday ... but was quiet about whether he would attend Leonard Nimoy's funeral.

Shatner tweeted on Saturday ... he would not be able to go due to a charity event he had scheduled in Florida -- however our photog shot Captain Kirk after his flight landed around 11:30 AM today.

He remained tight lipped about whether a backlash from fans made him change his mind about paying his last respects to Spock. We reached out to his rep ... but so far no word back.

Shatner did talk to us about Terry W. Virts ... the astronaut who paid tribute to Spock by giving Earth a Vulcan salute from space.

2:50 PM PST -- Nimoy's rep says the funeral was at 9AM this morning ... which means Shatner was still in the air during the service.