Read the following passage and mark the letter A, B, C or D to indicate the correct word or phrase that best fits each of the numbered blanks.

Air-travel is the most modem form of ___(1)___ transport and it ___(2)___ in the 20th century. Millions of people use airplanes for a variety of reasons. It is also extremely expensive to set up air-travel facilities. Some travel for business, others go on holiday ___(3)___ air and others use cargo planes to move their products from country to country very ___(4)___. Some courier companies now have their own fleet of planes ready to carry parcels and post more efficiently. There are different types of passenger services - some arc cheap and provide a ‘no-frills’ service which is good for short journeys. Other airlines provide passengers with a luxurious flying experience. Airports are getting busier and it is evident that ___(5)___ passengers and businesses than ever are using airplanes to get to their destinations.