Originally Posted by
chevvron
Nothing to stop an operator filing an IFR flight plan in Class E airspace however I'm thinking in terms of UK rules rather than USA rules.
No of course not ., also in the US , it is not filing an IFR PLN which is the issue for me but doing so with a fast jet at low altitude. Although E is officially a "controlled: airspace , separation with VFR is not assured, It is one thing to cross it climbing or descending , as done regularly , but a bit less for an Airliner cruising for over an hour in it at low altitude