Melbourne plane crash victim improves

A flight instructor and his student remain in hospital - one fighting for life, the other in a serious condition - after their plane crashed in a Melbourne paddock.

The ultralight Bristell two-seater crashed at Clyde North on Thursday morning, leaving one of the men trapped in wreckage for more than an hour.

A man aged in his 20s was initially listed as critical but a spokesman from The Alfred hospital on Saturday said he had improved slightly and was in a serious but stable condition.

A second man, believed to be in his 30s, remains in Royal Melbourne Hospital in a critical condition.

The aircraft was registered to Learn to Fly Melbourne, which is based at Moorabbin Airport.

Civil Aviation Safety Authority spokesman Peter Gibson says the ultralight was on a training flight when it crashed.

"It was on a dual training flight with an instructor and a student on board," Mr Gibson said on Thursday.

Recreational Aviation Australia is investigating the crash and spent Thursday and Friday assessing the scene.

A report is expected in the coming weeks.