填空题

In recent years, there has been a big increase in air travel and many large airports have now reached the limit of the number of aircraft movements they can (36) The problem is made worse by the size of many major cities which prevents the (37) of existing airports. Any new airports to be built a long way from city centers will create (38) problems arid in many countries there simply isn’t enough land for such developments.
Now a new (39) has been put forward which would help to (40) the congestion, as far as short flights are concerned. This (41) the use of smaller aircraft, carrying about 50 passengers, which only require a short take-off or landing area and which make (42) little noise because they are propeller-driven.
The main problem (43) is the question of noise. (44) , that any government can expect to find considerable resistance to building new airports in towns, even though these short-range small planes are relatively quiet. (45) if they can have the conveniences of an airport near the city center. In the end, (46) .