I had an interesting conversation today. It would appear that the airport to the east was not the first choice for the budget airline based in the north of England that recently made an announcement! My source is impeccable.
Bit late now...
There is no way the airport could have accommodated a new base for Jet2 with eight aircraft from next summer. Unless Monarch or Ryanair were to suddenly leave the airport.
What's done is done, and highly unlikely Jet2 will move in the years to come, if the base at STN matures well and they get a good loyal customer following, which is what they seem good at doing, up north.
How many stands did the airport have before the expansion started and how many will it have once complete?