I don't think it would make any sense, to be honest.
Stobart Air seems to have very significant liabilities - underpinned by Stobart Group which is why the Group bought it back from the administrators of Flybe as it was cheaper for them than the administrators calling in those guarantees. If you are now looking at starting a new airline to fly for Aer Lingus, you have a broad choice between acquiring Stobart and taking on those liabilities plus whatever debt has been built up through the Covid-19 survival efforts or starting from scratch with a clean balance sheet and only whatever debt you need by way of start-up financing.