V 意向形 + とする/と思う

Initially I was trying to form sentences like I was about to do something.

買おうとしていた。
Was about to make a purchase.

But then realize していた part is just a conjugation of する.

航空券を買おうと思ってたけど、多分明日にする。
I was thinking about buying a plane ticket but I’ll probably do it tomorrow.

• V 意向形 + とする about to do something (closer to doing it)
• V 意向形 + と思う thinking to do something (still in my head)