Q:

Simple Present / Formal Future use in this sentence

This question on ELU asked

In this sentence "Look at the timetable. Hurry up! Flight 4026 takes off at 6:20." Can I replace "will take off" with "takes off"？

A user commented on the question like this 

They do not mean the same. The Simple Present Tense (Present Indefinite) is used for something that happens regularly/ usually/ normally -- Flight 4026 (generally) takes off at 6:20 . On the other hand, the formal future tense will+verb indicates a (definite) possibility in the future

and I asked that user this question

Are you saying that it would be incorrect to say The plane takes off at 6:20 in the case where that route and timing had never been flown before and will never be flown again by that plane ?

They kindly directed me to ELL for an answer, so here I am asking the question
Is it incorrect to say The plane takes off at 6:20 in the case where that route and timing had never been flown before and will never be flown again by that plane?

A:

It does not matter whether it has ever flown before or it's only flying one time. 
The simple present can be used for something that is happening for sure (irrespective of the number of times it has happened in the past or will happen in the future).
See these -

The movie starts in 10 minutes - Talking about the movie which is starting in a few minutes. It could be for a movie that has never been shown before i.e. this is the first show. Nor am I talking about the future shows of the movie.

In the same way,

The train departs in 10 minutes, hurry - I am concerned about the event that is happening for sure in the future. 

So, you can say that whether the flight happens to be for the first time or for the last time. 

