As regards Open skies, that will be on the table, along with access to the EEC free trade market. Your status as a net importer will stand to you here, but full access to the free trade market would require unrestricted movement of EU citizens into the UK a la Norway/Iceland/Switzerland....which was one of the big pro leave side's bug bears. Open skies will also feature in those negotiations as well as God knows how many other things.
But not EFTA member Liechtenstein.
That EU rule about non-EU companies not being allowed own more than 49% of EU airlines will be gone, so DAL can swallow up VIR.
Who knows, the UK may have its own arrangements. As a UK carrier can't "swallow up" a US carrier, it's doubtful that the reverse will be allowed. These things are usually reciprocal.