Keflavik is the main international airport serving Reykjavik .
It is Icelandair's main base from where they serve North America and the main airports in Europe including Heathrow.
Reykjavik airport is really a commuter airport handling mainly turboprops on domestic services in Iceland ,plus services to Greenland the Faroe Island.
I suspect this is why Keflavik wasn't highlighted in Easyjets press release , as serving Keflavik from Europe is the norm.