Airdrie were left on the wrong side of Championship play-off history again, as a Simon Murray penalty gave Queen's Park a narrow win at New Broomfield that sees them promoted instead.
The Diamonds had taken the lead through Rhys McCabe's superb free kick, but Queen's Park levelled through Connor Smith.
They bagged their winner in the second period of extra-time when Dylan Easton fouled Simon Murray and the former Dundee United and Hibs striker dusted himself down before sending his side up to the Championship.
That's hard for Airdrie to take, having pushed champions Cove Rangers so close this season, but an other season in League One beckons for them.
The first half was fairly even, with Rhys McCabe putting Airdrie ahead in 13 minutes with a superb free kick, but that lasted just five minutes before Connor Smith drew Queen's Park level.
However, the visitors forced a few fine saves from Max Currie to keep the scores level.
It was much the same in the second half, with both sides obviously trying to win it, but Airdrie stepped up a gear and pushed Queen's Park towards the end.
Queen's Park dominated the first period of extra-time, with some last-ditch defending and near misses keeping Airdrie in it.
But Murray's penalty was the difference for the Spiders, who will move up a league next term.
Diamonds boss Ian Murray made one change to the side that drew 1-1 in the first leg, as Jon Afolabi started in place of Gabby McGill, who was on the bench.
Queen's Park gaffer Owen Coyle made two switches, with Liam Brown and Louis Longridge in for Jake Davidson and Jai Quitongo, both of whom were on the bench.
Airdrie nearly took the lead in the first three minutes when Calum Gallagher found space on the right and picked out Dylan Easton, but his top corner-bound shot was superbly pushed away by Callum Ferrie.
At the other end Simon Murray broke clear on the right and crossed for Luca Connell, but he failed to connect properly with his shot and the danger was cleared.
Airdrie took the lead in 13 minutes when Jon Afolabi was fouled just outside the box and McCabe fired the free kick straight into the bottom left corner.
Queen's levelled in 18 minutes when Airdrie failed to clear their lines and Connor Smith's curling shot beat Max Currie, via a deflection.
Luca Connell went close in 27 minutes, but Currie superbly pushed his shot away from the left corner.
Queen's started to edge the game and in 35 minutes Longridge saw a long-range effort pushed past the left post by Currie.
Airdrie's next shot on target was slightly unorthodox, as Adam Frizzell tried a drive from the right hand side of the box, which was well taken by Ferrie at the near post in 40 minutes.
Afolabi showed some great strength to make his way forward in 48 minutes, but his fierce shot was taken at the second attempt by Ferrie.
Airdrie were denied what they thought was a penalty in 58 minutes for a foul on Easton, but play raged up the other end and Connell sent a curling shot just wide of the left post.
The Diamonds should have gone ahead in 67 minutes when Easton slipped Gallagher through on goal, but he hesitated and Michael Doyle was able to make the saving tackle.
Murray ran through the middle in 71 minutes and when his way was blocked, Smith picked it up b but saw his shot from a tight angle pushed onto the right side-netting.
Queen's Park went mightily close to taking the lead in 82 minutes when Murray sent Smith down the right, but his driven cross flashed across goal with no takers.
Smith then tried a lob, but sent it over the bar.
Airdrie ventured up the other end in 84 minutes, with Adam Frizzell's shot deflected just over the bar.
McCabe's long throw-in from the right reached the back post, where Scott Agnew's shot was well saved by Ferrie in 85 minutes.
Airdrie nearly nicked it inside stoppage time when Agnew picked out Frizzell in the box, but his swerving shot landed the wrong side of the right post.
Into extra time we went, and Queen's Park nearly drew first blood five minutes in, but Murray's cross from the left was headed just over by Bob McHugh.
Murray went on another run down the left, with his cutback fired just past the near post by Smith.
Airdrie were on the ropes at this point and Murray played a neat one-two with Jai Quitongo before seeing his shot blocked as Queen's Park tried to turn the screw.
Queen's Park won it late in extra-time when Murray went down under a challenge by Easton, with referee Steven McLean pointing to the spot.
Murray nearly bagged a second 27 minutes in, but saw his shot pushed just past the right post.
The Queen's Park striker had another go at making sure in the final minute, again seeing his shot pushed past the right post.
AIRDRIE: Currie, Watson, McCabe, Fordyce, Paterson, Agnew, Afolabi (G. McGill, 77), Frizzell, Easton, Smith (S. McGill, 99), Gallagher (Allan, 90+2).
Subs (not used): Cantey (GK), Kerr, McDonald, Walker, MacDonald, Devenny.
Booked: Agnew (79), Easton (79), Paterson (107), Allan (114)
QUEEN'S PARK: Ferrie, Doyle, Grant (Kilday, 98), Fox, Robson, Brown, Lyon (Thomson, 78) , Longridge (McHugh, 68), Connell (Quitongo, 90), Smith, Murray.
Subs (not used): Heraghty (GK), Davidson, Longstaff, McBride, Darcy.
Referee: Steven McLean.
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