At low levels , especially , pilots were often forced to fly with the canopy removed .
The cockpit would get uncomfortably hot and they were not confident it would be possible to jettison the canopy in case of an emergency .
At low levels , especially , pilots were often forced to fly with the canopy removed because the cockpit would get uncomfortably hot and they were not confident it would be possible to jettison the canopy in case of an emergency .