These de Havilland DH 82A Tiger Moths are all nicely lined up on a frozen lake.
The lake wasn't the only frozen object - imagine the pilots in the open cockpits!

These Challengers have a number of advantages over the Tiger Moths. Two of the most readily apparent are:
(1) The Challengers have enclosed cabins with the ultimate winter luxury - cabin heaters.
(2) The Challengers have one less set of wings to brush the snow off!