Mr McKeague was 23 when he vanished in the early hours of September 24 2016 on a night-out in Bury St Edmunds, Suffolk.
Earlier this year, an inquest recorded in a narrative conclusion that Mr McKeague got into a bin that was then emptied into a waste lorry.
His mother Nicola Urquhart greeted mourners outside the church at RAF Honington, where he was stationed, as the City of Norwich Pipe Band played ahead of the service on Saturday.
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Mr McKeague's brother Daroch McKeague and sister-in-law Cloe McKeague were among those to appear at the ceremony at around 11am.
Attendees were pictured wearing yellow, blue and green after the family encouraged mourners to wear bright colours to the service.
Station Commander Group Captain Dutch Holland said in a statement: "I am privileged to have the memorial service for SAC Corrie McKeague today here at RAF Honington where he spent his RAF Regiment career.
"This memorial service is an act of worship led by a RAF Padre and we ask that the family's privacy is respected before, during and after this service as they remember the loss of a son, father and brother.
"Our thoughts continue to be with SAC McKeague's family, friends and colleagues and all those whose lives he touched."
Mr McKeague died at about 4.20am in Bury St Edmunds as a result of "compression asphyxia in association with multiple injuries", jurors at the inquest recorded.
Writing on the Find Corrie Facebook page in July, Ms Urquhart said that she had "struggled to come to terms" with the findings, but "as a family we are ready to have a memorial for Corrie".
"The Royal Air Force are holding a military memorial for Corrie for us," she said.
"I will never be able to thank the RAF for all they have done and tried to do for us, for all they did for Corrie."
She added: "As this is on public ground and not on the actual RAF base, anyone can attend the service."
The family have also requested no flowers and instead took a collection for the RAF Benevolent Fund.