AENA, Norwegian and El Al
The sale of a major stake in the airport operating company will in itself have no immediate impact on flights or routes. In a few months, depending on how the business is structured, the relationships AENA have in Spain may be used to leverage additional business for LTN. I can't see that resulting in new flights starting until W14.
Norwegian may be the subject of rumours, but they are well entrenched at Gatters, and IMHO unlikely to split their London operation. Gatwick are doing everything they can to maximise their efficiency and sweat their assets, like pricing operators of smaller aircraft out to create space for the likes of NAS.
In the past, El Al operated TLV-STN-NYC, so it's possible they could revive the routing but through LTN. As a result El Al will be best placed to understand the economics of such a service. Runway performance may be an issue.