Possible Clues:

• On the face of it they get sent, by the sound of it
• Thin margins
• Fronts of planes
• Mr. Potato Head pieces
• Leading airplane features?
• They get sound of what's sent on ahead
• 'On the face of it, they sound as if they get sent (5)'
• Clowns' costume essentials
• Brandy sniffers
• They can be kinda stuffy