To be exact, we have two ways of air shipping. One way is called by express like by DHL/Fedex etc. Another way is called by air with airline company.
For example if you need to ship 1kg from China to UK, it is impossible to book separate air shipping space directly with airline company. Normally we will ship the 1kg for our customers via our DHL or Fedex account. Because we have larger quantity, so DHL or Fedex give better price to our company . That is why our customers find it cheaper to ship via us by express than the price they got from DHL/Fedex directly .