I had a project to take of or land in every European state, and it was quite a game. I'm still missing the Vatican, Ukraine (although I land crossed into it a couple of years ago) and Russia, plus Seeland depending on what you consider a state.

San Marino was the most fun and came from a very lucky encounter with an Italian pilot whose mentor was a U2 pilot who ran the San Marino aeroclub and was able to clue him in on the grass runway heading uphill; Andorra (helicopter tour) the most picturesque.

Blade were offering €199 transfers when I looked yesterday to Monaco, but could be an old site I suppose. I went by helicopter and came back on the train. The best (cost/distance) helicopter flights you can do are the subsidised ones, for example Malaga to Ceuta with great view of Gibraltar, and also Foggia to the Isole Tremiti.