From memory there has nearly always been an IT operation out of Liverpool going back to days or Laker 1-11s in early 70s may be even earlier with Eagle but those are before my days
and most have run operations from both LPL and MAN.
Jet2 are adding a lot of extra aircraft to their fleet which have to be filled I mean 9 738 this winter alone plus the A321s and only 2 757 and maybe a couple of 733 leaving so in effect no aircrarft are being pinched from anywhere.
As for United to FAO 4 days a week on a really knackered 757 which I know people were not keen on travelling on as time keeping was awful as were Americans