mmmm, so this is quite complicated. An airline is allocated a number of night slots per season and then someone in the planning department has to allocate these by flight number and date. Must be quite difficult to manage on all sides.
How does a landing PIC make the decision whether to use a night slot or not - is this done at flight planning stage or over the english channel?
Does use of a night slot require prior approval from LHR?
Can be fun when BAW get to the last week of the season and have 100 spare night slots?