tests/data/flights: Fix date types
tests/data/flights: Fix date types

Turbo87/skylines,Harry-R/skylines,skylines-project/skylines,Harry-R/skylines,skylines-project/skylines,RBE-Avionik/skylines,shadowoneau/skylines,Turbo87/skylines,Harry-R/skylines,shadowoneau/skylines,Harry-R/skylines,RBE-Avionik/skylines,RBE-Avionik/skylines,skylines-project/skylines,skylines-project/skylines,shadowoneau/skylines,Turbo87/skylines,Turbo87/skylines,RBE-Avionik/skylines,shadowoneau/skylines