Darren Taylor, 49, was among patients who wanted to pay tribute to Yorkshire Air Ambulance during the party at the charity’s airbase at Nostell near Wakefield.
Agricultural contractor Mr Taylor was working on a farm at Towton near York on October 10 2013 when he became trapped in a potato harvester while trying to clear a blockage.
He was trapped for 25 minutes before he was discovered and emergency services contacted.
Mr Taylor, from Tadcaster, bravely endured a lengthy ordeal before he was freed from the machine.
He suffered major crush injuries and was flown to Leeds General Infirmary for emergency surgery.
Mr Taylor lost his left leg, the bottom of his right leg and severely damaged his left arm.
He was in a coma for eight days and spent three months in hospital.
Mr Taylor, who is now working full-time again, said: “If it wasn’t for the air ambulance I would probably be dead. I owe them my life - they are just fantastic.”
His wife Nicky Taylor, 51, said: “They are exceptional. We are grateful for everything they have done for Darren.”
Mr Taylor had a lengthy conversation with air ambulance paramedic Pete Vallance, 53, after meeting him for the first time since the accident.
Mr Vallance said: “It was fantastic to see Darren. His mental strength to recover from that and get back working is a credit to him.
“To see someone who has not only survived, but is back to leading as normal a life as he can is really humbling for us. It makes the job worthwhile.”
Also at the party was Scott Housley, 72,of Harrogate, who suffered serious head injuries when he fell while walking near Clapham in the Yorkshire Dales in February.
Mr Housley, who was airlifted to Leeds General Infirmary for treatrment, is now a volunteer fundraiser for Yorkshire Air Ambulance.
He said: “They probably saved my life and certainly prevented any life-changing impacts from the injuries.”
De Neil Sambridge is one of 11 consultants from Yorkshire hospitals who work shifts for Yorkshire Air Ambulance.
Mr Sambridge, a consultant anaesthetist at Sheffield Teaching Hospitals NHS Trust, said: “Ultimately we exist to save lives and help people in their time of need.
“To be part of that is incredible.”