Need advice on extending my vacation beyond approved leave

We are visiting the USA for vacation, but during our initial discussions my manager did not allow leaves for the entire month of December. Later I made a plan saying I would take only three weeks of leave, for which he said he got me an exception and asked me to use it judiciously. But we have already booked our flights.

I have approved leave only until the 23rd of December. Since the US team will be on holiday from the 26th and won’t be logging in, I’m planning to stay online on Slack and pretend I’m back. Is this a good plan? I mean, during the last week of the year who actually works? Even if I come back I will just sit and stare at the computer. I wanted to experience Thanksgiving with my family and cousins, and I do not think I will travel to the USA often. What do you all think?

One thing, My manager works from the USA.