Possible Clues:

• Words formed by plane's smoke trail
• Airborne advertising that debuted in 1922
• Aerial text, or the asterisked clues' answers?
• Message made by pilots
• Gives an airing to what's close to The Sun's view - is that leaving a message we can all look up to?
• It's sort of flighty advertising Native Americans would read as smoke signals
• Messages created by planes
• Script given to broadcaster generating letters on air
• Activity that's character-forming in a highly visible way
• Messages left up by exhausted fliers