Suzi Dorbon, an aircraft mover at Signature Flight Support, became trapped in a mechanically operated doorway at Luton Airport in 2015.
The 47-year-old's injuries were so severe they caused brain damage and she is in a persistent vegetative state.
St Albans Crown Court heard Signature "took no steps" to monitor the way staff were operating the doors.
Prosecutor Catherine Rabaiotti said the hangar has two doors, each with three sections which could be moved horizontally along tracks.
She told the court the company provided "short training sessions" to staff on how to operate the doors but that a risk assessment document failed to identify steps to reduce the crushing risk.
Judge Andrew Bright QC said: "In particular, staff were not told of a specific distance to stand back from the doors when operating them, nor were they provided with any follow-up or refresher training.
"Had the defendant done so, it would soon have become apparent that the way in which some employees were moving the doors was unsafe."
Mrs Dorbon - who lives in Barton-Le-Clay in Bedfordshire - is still in a coma at a care centre in St Neots and her husband Mick has given up his job to look after her.
Signature was fined £250,000 after pleading guilty to failing to ensure the health, safety and welfare of employees between 28 March 2014 and 28 April 2015.
The company said it had retrained staff, installed new warning signage and painted yellow lines on the floor to show workers how far to stand back from the doors.
A company which handles private jets has been fined £250,000 after a worker was crushed in a doorway.