The flashback of "Day of the Dumpster" showed the Rangers flashing their weapons. They did not get their weapons until the episode "Teamwork" and the clip was actually from the episode "Different Drum".
When Kimberly has the flashback of the first time she used her Power Morpher to become a Ranger, she and the other Rangers were wearing different clothes before they morphed into their Power Ranger uniforms. There were also two Putties present, one of which scratched its head in confusion after they became the Power Rangers. This flashback did not contain footage from the first episode "Day of the Dumpster," but rather from the unaired pilot.
When Kimberly comes in for a landing in the plane, the flaps are down on the plane. Alpha never told her to lower the flaps, revealing that a professional pilot was doing the landing.