Planes, as in plural.
( Planes ( , ( ( as ( in plural ) ) . ) ) )
(ROOT (FRAG (NP (NNS Planes)) (, ,) (PP (RB as) (IN in) (NP (NN plural))) (. .)))
Multiple planes.
( ( Multiple planes ) . )
(ROOT (S (VP (VB Multiple) (NP (NNS planes))) (. .)))