-If you work on straight salary, it is likely that you will have a travel budget (standard for the institution) of $10,000 or maybe $15,000/year. For your first job I find it doubtful that this will be negotiable, and, even, if it is, there will be other negotiating points that are far more important.

-If you work on an "accounts received minus expenses minus deans' tax" basis, you will be paying for your own travel (before taxes, of course, since you submit your receipts). You can fly however you want, since it is part of your expenses.

-If you're invited to speak at another institution, paid for by that institution (won't happen until you have a national reputation in your field), expect to be reimbursed for coach travel.

-If a pharmaceutical or drug company is paying to send you to a sponsored meeting or conference, they may send you business/first class. These trips may be totally valid (e.g., you're developing a new device with them) or may be because they're simply shmoozing you for business. I've never obseved one that was truly quid-pro-quo. If they don't get what they want in return, these trips will, however, be few and far-between. And getting rarer because of potential bad press.