Heightened US-Iran tensions, reinforced by September 2026 US Treasury sanctions on remaining Iranian carriers and secondary penalties for service providers, have sharply reduced commercial overflights and landings in Tehran FIR despite Iran's formal openness. European and US regulators extended conflict-zone avoidance advisories through mid-November 2026, citing persistent air-defense alerts, sporadic maritime incidents near the Strait of Hormuz, and a fragile ceasefire holding since April. A brief full closure lasting roughly five hours occurred in early October amid renewed strike fears and domestic protests, prompting immediate rerouting by carriers. Traders weigh these enforcement and alert dynamics against any diplomatic de-escalation or scheduled regulatory reviews that could alter operational risk assessments in the coming weeks.