Although this is now totally irrelevant to Aurginy I will give this a go. There are a lot of problems with your proposition and hence why people see it as fantasy!
- The customer will still be liable to pay APD even as a connecting passenger. This would be equal according to HMRC to £137
- With your suggestion have you considered the crew do not start their duty in LCY? They start their duty in LHR as they are mainline crew, therefore operate the equivalent of two sectors to Shannon (LHR-LCY-SNN). Your suggestion would only work if the crew had another overnight in JER...ie. LHR-LCY-JER (o/n) JER-LCY-SNN (o/n) SNN-JFK (o/n) - JFK-LCY-LHR. To overnight another crew in JER for such a marginal route is lunacy. Let alone the flight duty limitations headache.
- Aircraft maintenance. One A318 lands at 10, departs at 4...so i'm guessing we are going to squeeze in a JER rotation inbetween much needeed maintenance, cleaning etc?
- Weather...are BA going to put at risk their flag ship route by operating the aircraft first to an airport known for diversions and been shut for days on end. How will the highly paying pax get to JFK if your ac is stuck diverting from JER. Remember they only have 2xA318, both are used on a weekday.
I honestly think you are looking at a very limited market. Look at the airlines over the years that have pulled off JER-LCY while using cheap, high density seated props. To run a 40 odd seater jet....crazy...let alone to connect to JFK...good luck
Maybe it's time to get back to Aurigny....
