Now Playing: Uber wants to test flying taxis

Now Playing: Uber expanding transportation offerings

Now Playing: Mom's grocery store maternity shoot celebrates all pregnancy cravings

Now Playing: Cardi B reveals her 'weird, crazy, spooky' pregnancy dreams

Now Playing: Mayim Bialik shares parenting tips as she talks raising boys in today's world

Now Playing: Could flying taxis soon be hitting the skies?

Now Playing: Kareem Abdul-Jabbar makes 'Dancing with the Stars' finals prediction

Now Playing: Countdown to the royal wedding: Who made the guest list?

Now Playing: What parents should know about inappropriate content on YouTube

Now Playing: Inside the 2018 Met Gala

Now Playing: Ex-college football player on trial for ex-girlfriend's murder

Now Playing: Man accused of ditching women on expensive dates

Now Playing: Voters in 4 states go to the polls in high-stakes primaries

Now Playing: Investigation underway into graduation video firestorm

Now Playing: First lady launches 'BE BEST' campaign

Now Playing: Homes, buildings destroyed amid Hawaii volcano emergency

Now Playing: Trump to announce decision on Iran nuclear deal

Now Playing: Ronan Farrow reacts to NY AG resignation

Now Playing: NY attorney general to resign after abuse report

Now Playing: This son saved his mom's life with an organ donation