A community group will host a public meeting tonight at Glacier Middle School to discuss Seattle-Tacoma International Airport's expansion plans, giving residents a direct forum to press questions about the growth program's scope and consequences.

The session, organized by local activists tracking the airport's development agenda, comes as Sea-Tac continues to operate near the limits of its physical capacity — a constraint the Port of Seattle has sought to relieve through a multi-year capital program that has drawn sustained opposition from surrounding neighborhoods over noise, traffic and air quality.

The SeaTac Blog first reported the meeting.

Why does tonight's meeting matter?

Community opposition has become a material variable in West Coast airport expansion timelines. Neighborhood groups near Sea-Tac have repeatedly mobilized against elements of the airport's growth plan, and public sessions like tonight's at Glacier Middle School serve as the primary venue where residents coordinate that response.

For airlines serving Sea-Tac — Delta, Alaska and a roster of international carriers among them — the stakes are practical. Any delay or redesign of gate, runway or terminal capacity projects ripples into slot availability, bank timing and network planning across the Pacific Northwest's busiest airport.

What is on the table?

The Port of Seattle's expansion agenda for Sea-Tac has included:

• Terminal capacity increases to accommodate sustained passenger growth
• Airfield and gate projects intended to ease congestion
• Mitigation measures — noise programs among them — negotiated with affected municipalities

Tonight's gathering gives opponents and residents a platform to question which of those elements proceed, and on what schedule.

The backdrop

Sea-Tac sits hemmed in by the cities of SeaTac, Burien and Tukwila, a geography that concentrates airport impacts on densely populated neighborhoods. That reality has made community sentiment a persistent factor in the Port's planning process, and it explains why a meeting at a middle school — not a regulator's hearing room — can shape the trajectory of a billion-dollar capital program.

Organizers scheduled the session for this evening at Glacier Middle School. Residents who attend can expect presentations on the current expansion plans and an open discussion of the program's local effects.

Whether tonight's meeting produces a coordinated response, a legal challenge or simply a airing of grievances will become clearer as the Port of Seattle moves to the next phase of its expansion timeline.