If I understand correctly, US domestic carriers' flights are repeated daily. Thus if flight 123 goes from airport X to Y to Z on, say, Monday, then Tuesday, flight 123 of the same carrier will also go from X to Y to Z.

But - what happens if the X->Y leg starts at, say, 23:00, and the Y->Z leg starts at 02:00 the next day? Is the same flight number used? Is it then the case that flight 123 goes, every day, from Y to Z and later in the day from X to Y?

Note: Let's assume no timezone changes to make things simpler.

  • Does this kind of flight fly in the middle of the night? In Europe most airports are closed from just after midnight till about 5 AM or even later.
    – Willeke
    Nov 20, 2020 at 18:54
  • @Willeke: Looking at figures from 2000-2008, there are about 20% as many flights departing between 23:00 and 23:59 than between 17:00 and 17:59. So, less, but still many. And their average air time is close to 2 hours.
    – einpoklum
    Nov 20, 2020 at 19:01
  • That are flight before midnight. In your question you mention flights leaving an airport at 2 AM. It is the scheduled departure time that gives the flight number/date
    – Willeke
    Nov 20, 2020 at 19:02
  • 1
    @Willeke: There are some flights which leave during the various hours of the night, as well. Much less than in daytime, but they exist.
    – einpoklum
    Nov 20, 2020 at 19:36
  • @Willeke: 2 am in Dubai or Qatar is often prime time. It's pretty standard for airports that are mainly connection hubs. Icelandair used to do this as well, but not sure about at the moment
    – Hilmar
    Nov 20, 2020 at 19:39

1 Answer 1


I couldn't find a US example, but it certainly happens internationally. EK 412 flies from Dubai to Sydney to Christchurch and the Sydney to Christchurch leg happens the next day.

But - what happens if the X->Y leg starts at, say, 23:00, and the Y->Z leg starts at 02:00 the next day?

Nothing much. They just fly as usual.

Is the same flight number used?


Is it then the case that flight 123 goes, every day, from Y to Z and later in the day from X to Y?

Yes . You can type EK412 into seatguru and for any date you get SYD->CHC at 7:50 in the morning at DXB to SYD at 10:15 in the morning.


I just recalled a domestic example. I was on a "direct" flight from Boston to Las Vegas. Turns out United defines "direct" as "both legs having the same flight number". It does NOT mean non=stop. It also does NOT mean it's the same plane, the same crew, the same gate or that it's a guaranteed connection. It's just a marketing ruse: they simply combine two random legs, give them the same flight number and advertise as the connection as "direct".

This particular itinerary had a stop in Denver. The first leg was delayed, and the second leg departed on time while the first leg was still in the air. So, yes, two identical flight numbers in the air at the same time, probably in the same air controller space. And I had to spend the night it Denver!

  • So if the DXB->SYD leg of Tuesday's EK 412 is delayed, it could conceivably be in the air at the same time as the SYD->CHC leg of Monday's EK 412. I guess one of them would get an alternative call sign in that case. Nov 20, 2020 at 20:49
  • It's possible that two EK 412s are in the air at the same time, but for both of them to be in the same air controller space, something must have gone seriously wrong, i.e. Mondays SYD->CHC leg would need to be delayed by 20-ish hours to be still in the air when Tuesdays DXB->SYD arrives.
    – Hilmar
    Nov 20, 2020 at 22:35
  • I've even seen at some point in search engine results (though not taken) a Las Vegas-Paris "flight" with a single flight number, but a stop somewhere (Denver? Salt Lake City? Don't remember...), and two very different planes (a 320 or 737 on the first leg and a wide body on the other one). Pretty weird gimmick.
    – jcaron
    Nov 21, 2020 at 13:09
  • How ATC deal with this is better suited for Aviation.SE; the OP only wanted to know the passenger side and moved it here.
    – StephenS
    Nov 21, 2020 at 17:26
  • @jcaron: exactly. Aggressive airline marketing has destroyed the term "direct" flight. The ONLY difference between many direct flights and a regular connecting flight is that both legs have the same flight number. It makes the "direct" search options in search engines pretty much useless, although most engines have caught up and replaced "direct" with "non-stop"
    – Hilmar
    Nov 22, 2020 at 13:02

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