http://style.fm/log/04_watch/watch14.html

Umakoshi-san said:
あと『エアマスター』のオープニングもそうなんですよ。途中で挿し変わった部分の原画がほとんど全部、羽山さんですね。

Most of these cuts come from the second version of the OP, which is present from #09 onwards.

Two cuts at 0:06 are BANK from #01 and are also used in the first version of the OP. The final two cuts are also present in both versions of the OP but were probably specifically animated for it.