Possible Clues:

• In airways, one horse loses its tail, another gains one
• Breathing passages
• Robin is prepared to install central heating pipes
• Brother makes up short distance with breathing tubes
• Filthy rich nob means to have air travel for life
• Bobtailed horse greeting airlines
• Choir travelling round North on British Airways
• Tubes of man visiting surgeon on island
• Respiratory airways
• Air passages booked originally by male Greek character