Estimate of travel expenses for a Colloquium abroad - what does this include? This summer I will (hopefully) be attending the Logic Colloquium 2015, as a Ph.D student in Logic. The organizers will make available Travel Awards for grad students, and I would like to apply. One of the requirements is an estimate of my travel expenses.

My question is: what does "travel expenses" usually include in this situation? I imagine airplane tickets and accommodation expenses are included. What else could reasonably be included in my estimate?

Thank you.
Tickets and accommodation are typically by far the largest items.  You can also include other transportation expenses, such as travel to/from airports (or parking fees if you drive your own car to the airport and leave it there).  You should generally choose the cheapest option that's not too inconvenient.  For example, an airport shuttle may cost much less than a taxi.

Meals can be handled in many different ways: sometimes there is a fixed per diem amount to cover such expenses, sometimes you can be reimbursed but need receipts, and sometimes meals aren't covered.  The per diem approach is generally easiest for everyone, but it depends on how much funding there is and where it came from.

Other forms of travel expenses are less common and may or may not be covered, but it can't hurt to ask.  Childcare is a particularly messy issue, because this can severely limit travel plans but conference organizers are not necessarily prepared to provide funding or local recommendations; still, it's worth asking about childcare if it's relevant.