Now Playing: Video shows in-flight terror as fire leads to deadly plane crash

Now Playing: MLB pitcher facing questions after old racist tweets surface

Now Playing: $3.9B contract confirmed for 2 Air Force One replacements: W.H.

Now Playing: 2 children recovering from possible shark bites off the coast of New York

Now Playing: Trump says he warned Putin not to meddle in U.S. elections

Now Playing: Sanders clarifies Trump's statement on whether Russia still a threat

Now Playing: Co-founder of veteran-led disaster-response group to be recognized

Now Playing: Suspected Russian agent ordered held behind bars pending trial

Now Playing: Firefighters trying to contain Ferguson fire, now more than 17,000 acres

Now Playing: Boys rescued from cave say they stayed still to conserve energy

Now Playing: Man accused of fatally shooting at least 3 arrested: Police

Now Playing: At least 3 killed in midair collision over Everglades: Police

Now Playing: Residents evacuated after massive gas-plant explosion

Now Playing: Powerful storms drench Northeast at height of rush hour

Now Playing: Democrats slam Trump's attempt at postsummit damage control

Now Playing: Russian gun-rights advocate accused of undermining political system

Now Playing: Amazon: Prime Day breaking records despite glitches

Now Playing: Trump: 'I have full faith in our intelligence agencies'

Now Playing: Police bodycam shows officer firing through windshield during chase

Now Playing: CEO gives his car to employee who walked 20 miles to work