I remember someone reporting a missing plane before, now it (kinda) happened to me.
I opened a route with 2 Il 96400 with around 6900 pax capacity.
I went away from the game for a couple hours and now that I came to check, it's like this:
Both blue sections are labeled as being Blue Sky (aka, ME), one with 6.9k (100%, 2 planes) and other with 2.2k (56%, 1 plane).
And that wasn't for only one week, it has been 3 weeks now and it's still like that.
My route shows as the one with only 1 airplane and 2.2k pax out of 3.9k cap, while the dupe has 2 planes and 100% occupancy. It shows that the capacity was 3.9k (1 plane) for a long time now.
So... I lost a plane, and I'm trying to compete with myself?
Also, I allocated 18 slots for the route (2 planes). The plane that was stolen from me took the slots with it, I lost them.
I have no idea what happened.
--- Edit:
Sorry, I forgot to say, the route is London Heathrow -> Cologne.
The "other me" isn't listed on the "Direct Competitions" list, only the 2 gray NPC's