It depends on what PhD you do and where.
There are PhD projects out there that do not involve flying... But you need to be honest about it and make sure they know it otherwise they might send you off to somewhere.. with a plane..
It also depends on where you live.
In europe its easier to get to other countries, but if you are from the usa and you need to go to europe or travel in the usa itself.. distances are bigger..
Its perfectly possible to do a PhD that doesnt even require lots of traveling...
However, when you have the PhD... the question then is: can you do research in your field.. because then often you have meetings, presentations in other countries far away...
It will stop you from doing certain jobs, but in the end: its harder, but not impossible...
(try to find a PI that is scared of flying too
, there are other people out there that are scared to flew too you know.. you are not the only one!)
Edited by pito, 22 May 2011 - 12:47 AM.