You are onto something, if I search in Czech for "cheap air tickets from Prague" I get better results:
Levneletenkyzprahy.cz[1], Jaknaletenky.cz[2], Levneletenky.org[3] and Skyscanner.cz[4] all offer flights from Prague to London, with prices ranging from 490 Kč to 1 200 Kč depending on the season and airline[1][2][3][5].
490Kc/22USD - 1200Kc/54USD
Not sure why is exactly London specific, but it's for sure more useful than those expensive US flights.
Levneletenkyzprahy.cz[1], Jaknaletenky.cz[2], Levneletenky.org[3] and Skyscanner.cz[4] all offer flights from Prague to London, with prices ranging from 490 Kč to 1 200 Kč depending on the season and airline[1][2][3][5].
490Kc/22USD - 1200Kc/54USD
Not sure why is exactly London specific, but it's for sure more useful than those expensive US flights.