Noticed yesterday mass crowds in the tiny Krakow terminal waiting for FR 1855 Krakow - Frankfurt (Hahn)

I arrived 3 hours after this was due to leave and the the 737 was parked outside.

When I left noticed the stairs and doors were open and engineers were in attendance (several cars around the plane), however when I actually departed it was all sealed up as if parked for the night.

The 737 was one of Ryanairs anti BA Aircraft.. "say no to BA Fuel surcharge" on the side, funny as the BA 737 flight to London was leaving on time.

Any ideas what was wrong with it / when it left ?