My mate flew and he said you can see into the cockpit, so when youâre getting buffeted around on landing you can see everything. After landing the pilots turn around and do a thumbs up.
I would try it, but I have a terrible fear of heights.
In some ways, I would say itâs worse as a tourist. You board the boat all happy and excited for the vacation. If youâre like me, you go to the back of the boat, open the door, head out onto the rear deck, and take pictures with your son with the boatâs wake in the background. Everybody in the boat is all smiles and laughing. Then after about 20 minutes, complete silence, which is interrupted every few minutes by the sound of someone puking. Then the smells. Your knuckles are white from grabbing onto the handrails of your seat. You look at your kids and wife with a look of concern on your face for how badly they must be feeling. And the agony goes on and on it seems like for an eternity and you swear to yourself ânever again.â I swear I never once thought of the former prisoners on Green Island during that time.
I sure did when I went through that.
It helped pull me through. 
Guy
So the sea around green island is rough? And Iâm guessing itâs very rough in the winter?
Why would anyone even think to sail a home made pontoon boat through that?
Youâre a better man than I am, Gunga Din!
Everybody complains about it. Not too bad on the way back. Itâs not a matter of getting used to it, itâs just a calmer ride.
I dislike ferries where you have to sit inside. I remember the ferries to Lanyu had seats at the back outside. Much fresher air, less torture.
So if youâre flying can you fly from the songshan airport? Is it more expensive?
I donât remember it being too bad when I went actually. Iâve had worse boat rides. Maybe I was just lucky.
I thought the flights are just from Taitung. The useful link that @rooftopclown posted above should be able to help though.
I think he has that site blocked on his phone 
The short hop to Green Island is from Taitung Airport. You can either fly from Songshan to Taitung, then connect to Green Island, or otherwise get to Taitung (say by train) and then catch the flight.
And yes the flight option will cost more.
Guy
Another thing I found out is there are 3 flights a day, and only 4 seats per flight are available! (it seems the rest of the plane is for people who actually live on the island). So you had to reserve the flight well in advanced.
Or, like normal people, take the ferry.
Guy
The problem is that the ferry doesnât run in bad sea conditions, so you might not be able to get back. And accommodation on Green Island can be expensive. I also may get seasick. Not to mention the higher convenience store prices because of the surcharge.
Sometimes the benches are occupied by goats too. Iâm not sure why thatâs a problem, but it might be. Where would I sit if I need a rest?
we have been stranded there a couple times as well due to bad sea. once for a week. it sucks, and costs a lot. but at the same time, the freedom to say F it, nothing I can do was liberating!
I will only fly to lanyu. I dont mind the flights. i just wont spend that much more time and money trying to fly to green. only a 40~70 minute puke session and a few hour to all day recovery 
My wife puked each if the 3 days we were there last time haha. ferry, snorkeling, ferry. lucky gal!
its worth a go. but if sea sick is a thing, make it a 2 night minimum and enjoy the middle full day 
Edit. a lot of people wait at the airport for cancellations. that happens often. and, at least before for lanyu,they had that dumb rule that people can reserve and cancel at the last minuteâŚbut thatâs more an aboriginal thing, maybe green island not?
The ocean is brutal. Green Island ferry too.
Double up on your seasickness patches and eat nothing that morning. Find a spot outside in the middle and stare at something on the horizon.
Or yeah, fly. 
Or book the flight well in advance
Iâve failed to get to Green Island once. There was a typhoon. A possibility to consider.