Airdrieonians missed out on a place in the Scottish League One play-offs despite beating second-placed Ayr 3-0.The visitors did what was required of them, having scored two goals in the opening 10 minutes, but Stranraer's win over Cowdenbeath prevented them from securing a top-four spot.Alan Lithgow opened the scoring in the third minute, the defender converting from close range, before Dylan Mackin netted a second when he found the top corner.Sean Crighton added gloss on the scoreline in the 79th minute to end Ayr's two-match winning run.