Deducting business travel expenses for partial work/holiday

I have an LLC, single employee (me). My LLC is a disregarded entity and I pay taxes on my individual tax return.

 

This summer I spent 3 weeks in Europe, a combination of holiday and work ("digital nomad"). I brought my laptop and performed 2 to 4 hours of work a day. None on the weekends. 

 

I'm seeking a definitive answer as to whether a 4 hour work day, aka 50% of what I billed my client, translates to a proportional 50% deduction of my business expenses for that day (e.g. meals). Or is the fact that I worked at all that day mean that I can claim 100% of the deduction? As for my flight from/to Europe, if I worked half the days on my trip, I was going to deduct half the cost of the flight. Is that correct?