As it turns out, Hayato and Kai never piloted the RX-78-2 Gundam, it was piloted chiefly by Amuro Ray, with Sayla Mass and Ryu Jose apparently having piloted the Gundam before.
Edit: Gundam Wikia is unreliable, as it turns out. Hayato apparently did pilot the Gundam.
SlummmpOkay, question: Who of the following has never piloted a Gundam? Amuro, Kai, Hayato, Ryu, or Sayla?We should all come back sometime!Well, for all that happened, it was fun!But before we do...!R-...Ryu?BeepC'mon, gimme a break, already!Not a chance.Zzwooom Dun-dun Dun-dunBzzzzt! For the correct answer, let's watch through once more to confirm!