Décoller looks like it literally means "Gluing off", actually sounds pretty accurate if we assume everything's glued to the ground - but planes can manage to defy that.
This is the near future. Both English and French commonly use the present tense for it, although you can use the future tense as well.
- Nous décollons dans quelques minutes - We are taking off in a few minutes
- Nous allons décoller dans quelques minutes - We are going to take off in a few minutes
- Nous décollerons dans quelques minutes - We will take off in a few minutes
In French "quelques" and "plusieurs" are not dramatically different, but at least you should know which is which, with their respective translations to English.
Given that this is referring to a take off in the future would this not normally be better expressed in "futur simple"
A statement like this is typical in the present tense in both French and English. You have asked the same question on numerous exercises through the Transportation section.