Giải thích tại sao Some travel for business, others go on holiday ___(27)___ air and others use cargo planes to move their products from country to country very ___(28)___. 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 ___(29)___ passengers and businesses than ever are using airplanes to get to their destinations. Question 27. A. on B. at C. by D. in Question 28. A. quickly B. quickness C. quick D. quicker Question 29. A. less B. much C. fewer D. more