https://en.wikipedia.org/wiki/Tier_1_network
Tier 1 network - Wikipedia
tier 1 networkwikipedia
https://aviationweek.com/air-transport/airports-networks/munich-airport-opens-tier-1-pier-extension
Munich Airport Opens Tier 1 Pier Extension | Aviation Week Network
Munich Airport officially opened the new Terminal 1 Pier extension on April 13, adding capacity for an additional six million passengers annually.
munich airporttier 1pier extensionaviation weekopens