The flight did not respond.
( ( The flight ) ( ( ( did not ) respond ) . ) )
(ROOT (S (NP (DT The) (NN flight)) (VP (VBD did) (RB not) (VP (VB respond))) (. .)))
The flight was unresponsive.  
( ( The flight ) ( ( was unresponsive ) . ) )
(ROOT (S (NP (DT The) (NN flight)) (VP (VBD was) (ADJP (JJ unresponsive))) (. .)))