what kind of aircraft does delta use before 8am on august second from boston to denver 
return flights ;return #1 from  boston ;return #2 to denver ;return #3 on  august second ;return #4 before 8am ;return #5 on  delta ;return kind of aircraft that  #6 uses
['select', 'filter', 'filter', 'filter', 'filter', 'filter', 'project']