Largest airborne telescope

According to Official Guinness Records,

Nasa's (USA) Stratospheric Observatory for Infrared Astronomy is a Boeing 747SP fitted with an infrared telescope with a 2.7m-wide (8.85 ft) primary mirror. 'First light' for the telescope occurred on 18 August 2004.
'First light' is the term used when a scientific observation instrument, such as a telescope, is first tested - ie the first light hits the detectors.

For a complete list of 2004 records, please visit 2004 Guinness Records in United States.

Other United States records that might interest you:

• Longest skateboard ramp jump
• Oldest cat ever
• Highest jump on a hydrofoil
• Tallest climbing rose
• Most expensive RPG (Role Playing Game) product