The article on the Gazette's website certainly reads like this summer, but the press release on the TVCA website is clear that it is 2021
Balkan Holidays has today (Tuesday 4 February) announced that it is doubling the number of its flights to Bulgaria from Teesside International Airport for summer 2021, following excellent sales for its 2019 and 2020 services.
Teesside Airport Doubles Summer Sun Flights With Balkan