Radar data show the Otis fighters were airborne at 8:53.
( ( Radar data ) ( ( show ( ( the ( Otis fighters ) ) ( were ( airborne ( at 8:53 ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Radar) (NNS data)) (VP (VBP show) (SBAR (S (NP (DT the) (NNP Otis) (NNS fighters)) (VP (VBD were) (ADJP (JJ airborne) (PP (IN at) (NP (CD 8:53)))))))) (. .)))
The fighters never took off and stayed on the ground.
( ( The fighters ) ( never ( ( ( ( took off ) and ) ( stayed ( on ( the ground ) ) ) ) . ) ) )
(ROOT (S (NP (DT The) (NNS fighters)) (ADVP (RB never)) (VP (VP (VBD took) (PRT (RP off))) (CC and) (VP (VBD stayed) (PP (IN on) (NP (DT the) (NN ground))))) (. .)))