hi, there, I was just randomly wondering around in this BBS. Currently I'm hesitating to switch from Transportation Planning & Engineering to Aviation and Aerospace Engineering for my PhD. I've never worked a single day in this industry, not sure how it works. Do you have facebook or wechat that I can add you to my friend list so that I can ask you about it? I mean, if you don't mind. I'm studying at the University of Waterloo in Canada.