Flight DL187 to Los Angeles is declaring an emergency and returning to London Heathrow.
Flight Delta Airlines 187 has declared an emergency over Scotland.
The Airbus A330-900 performed a U-turn over Glasgow.
The flight is returning to London Heathrow after one of the flight deck crew felt unwell.
The aircraft is only one year old, registration N414DZ.
UPDATE #1 19:01 BST Two flights are now on hold to allow priority for #DL187 landing.
UPDATE #2 19:04 BST Delta #DL187 is on final to runway 27R.
Yesterday, Virgin Atlantic flight to LAX also declared an emergency in a very similar situation before returning to London Heathrow.