Possible Clues:

• Silly laughter? A measure of gravity becomes British pilot
• Pilot in book, with slight worries, scratching head
• Hero of books by WE Johns
• Hero created by Captain W. E. Johns
• Pilot, prominent, with artificial legs
• Pilot light's first to go in most enormous short
• Fictional pilot and adventurer created by W.E. Johns
• Fictional Royal Flying Corps hero
• Air ace created by Captain W E Johns
• Large sort of legs for flying ace