"I like high places, y'know. I bet in a past life I was... an airplane?" "Normally you'd say 'a bird,' you know."
Literal
"High places [topic-って], I [topic-は] like [reflective-だなぁ]. I [topic-って], previous-life [topic-は] surely... airplane was [wonder-のかな]?" "Normally, there [topic-は] bird [isn't-it-でしょうが]."
A comedic dialogue. The first speaker uses あたし (casual feminine 'I') and the reflective なぁ. The joke is the unexpected 飛行機 ('airplane') where 鳥 ('bird') would be the natural answer. 前世 (ぜんせ, 'past life / previous incarnation') is a Buddhist concept used casually here. The second speaker's ツッコミ (straight-man response) uses 普通 ('normally') and でしょうが — the rhetorical でしょう + が, meaning 'it should be [X], shouldn't it!' A classic ボケとツッコミ (funny-man/straight-man) exchange.