Deducting travel expenses for charitable mission work

I'm a doctor and did a foreign medical mission trip run through a 501c3 nonprofit. I've looked through Turbotax and IRS Pub 526 and understand that my travel expenses for this trip are likely deductible but have a few questions.

 

Do I take the deduction in the year I incurred the expense or the year of the trip? ie book flights in 2022 for trip in early 2023, pay for hotel at checkout in 2023 - must the expenses from this trip be split across my 2022 and 2023 returns?

 

If I paid for an upgraded seat on my flight, any issue with deducting that as well as the base airfare?

 

If I had meals on the trip where I do not have an itemized receipt but can document the expense via a credit card charge on my statement, is that enough, or would claiming that be looking for trouble?

 

Thanks for your help!