Here are the possible solutions for certain landing aid clue
Answer
Clue
Relevancy
pontoon
Clue
Certain landing aid
Definition
a flat-bottomed boat or barge, also PONTON
retrorocket
Clue
Lunar landing aid
Definition
a rocket whose function is to slow down, fired in a direction opposite to that in which a body, e.g. a spacecraft or an artificial satellite, is travelling