a) Domestic airports only handle flights within a country, while international airports handle flights to and from other countries.
b) Domestic airports only handle cargo flights, while international airports handle both passenger and cargo flights.
c) Domestic airports only handle small aircraft, while international airports handle large commercial aircraft.
d) Domestic airports only handle military aircraft, while international airports handle civilian aircraft.
Answer: a) Domestic airports only handle flights within a country, while international airports handle flights to and from other countries.