The charter airline business was highly seasonal, with most of the annual commercial activity taking place over a relatively short period of barely four months between the end of May and the beginning of September. As Air Europe was operating a fleet of brand-new aircraft that incurred high financing charges unlike the older, second-hand jets operated by Dan-Air and many other rival airlines, it could not afford to kerb its fleet utilisation over the winter months. Dan-Air, by contrast for example took half of its operational Comet fleet out of service at the end of the 1976 summer season and put the aircraft into storage at Dan-Air Engineering's main base at Lasham Airfield the following winter season and saw reduced use of other aircraft in the winter. Dan-Air was able to do this as these predominantly older, second-hand aircraft had much lower acquisition costs and were already largely or fully depreciated at the time they entered its fleet.