Article + day trip

Not the same question! Don't want to break any rules. I have asked a similar question, but I think it was a bad example. I would like to re-formulate.

"What have you got planned for next week?"
"Lots of things. Plus I have a day trip on Friday."
"Lots of things. Plus I have the day trip on Friday."

"A day trip" implies that I am not sure if you know that I have a day trip. In any case, I am reminding you of it.

"The day trip" means that you definitely know the day trip I am referring to. It's that day trip and it will take place on Friday.


Either is correct. Depends on the emphasis.

Correct?