unavoidable (adj): impossible to avoid or prevent
airspace (n): the part of the sky where planes fly, usually the part above a particular country that is legally controlled by that country
austerity (n): a situation when people do not have much money to spend because there are bad economic conditions
stowaway (n): a person who hides in a ship or plane before it leaves, in order to travel without paying or being seen
undercarriage (n): the part of an aircraft, including the wheels, that supports it when it is landing and taking off
brew (v): to make beer
quadruple (n): one of four children born at the same time to the same mother