Fill in the Blanks (Reading & Writing)

Regional airports serve smaller cities that —lacklackingare lackinglacks enough passenger traffic to justify a major international hub. They often depend on a single dominant carrier and a handful of domestic routes, which leaves them —vulnerablevulnerabilityvulnerablyvulnerable to be to airline scheduling decisions. Despite this fragility, many local governments continue to —promotepromotionpromotingpromoted such airports as engines of tourism and trade.