Originally Posted by
IHBvet93
I periodically check flight status on Delta's website, and normally they run two daily flights DTW-LHR: Flight 16 departing 6:16PM and 18 departing 10:37PM.
On either Monday or Tuesday, a third flight was listed. The flight number was four digits (believe began with 9), with scheduled departure within 5-10 minutes of 16. This flight used a 767.
This "extra" flight is not on offer on today's schedule (July 18).
Any idea if Delta ran this flight strictly for heavy general summer demand, or if it was a one-off prompted by, say, a large group enroute to a convention?
Four-digit flight numbers that start with a 9 are used for non-scheduled flights. Sometimes charters, maintenance, or replacement/recovery flights. Given some of the recent Midwest weather I would guess that this was a recover/replacement flight for a flight that was either severely delayed or cancelled from the day before.