In passing, I’ll often talk about IATA summer and winter schedules, though it occurred to me that I’ve never written in detail about what those are, and why people should care. For airlines, there are two key dates every year that have a big impact on network planning, so let me explain what those dates are, and why.
So, why do the IATA seasons matter? Most concretely, for the airports that are slot controlled, slot allocations happen seasonally. So if an airline gains or loses slots (this can happen for a variety of reasons), those slots have to be used with a schedule that coincides with the IATA summer or winter season. Also keep in mind that slots have a “use it or lose it” clause, so airlines have to use those slots if they want to keep them.
So my point is to say that you’ll typically notice the biggest airline changes coinciding with these seasons. That could include frequencies or routes being added or eliminated, aircraft types or certain configurations being reassigned, etc.
A great solo travel tip spotted this week on One Mile at a Time.




