In the show there were two different types of helmets used, known as 'stunt' and 'hero'. The 'stunt' helmet was the one used by the pilots who flew the 76s. It was literally just a shell wrapped around a headset that had no features. The 'hero' helmet was the one used by the actors in the 88k known as the stage lady. The 'hero' contained a lot of features, like a visor that would slide down, and lights. It was powered by an amplifier.
In some scenes you could see the actors also wearing the 'stunt' helmet. Primary due to scenes required to be filmed in 76s.
Screen used 'STUNT' helmet worn by the pilots.
Jan wearing the 'STUNT' helmet in the episode 'AND THEY ARE US..'
Ernie wearing the 'STUNT' helmet in the episode 'ONE WAY EXPRESS'
3rd Season 'HERO' helmet with control box for the visor and electrics.
Publicity still of Jan with the 'stunt' helmet