ETA vs STA vs ELT: Aviation Time Acronyms Explained

The big ones

• STD — Scheduled Time of Departure.
• STA — Scheduled Time of Arrival.
• ETD — Estimated Time of Departure.
• ETA — Estimated Time of Arrival.
• ATD — Actual Time of Departure (wheels-up).
• ATA — Actual Time of Arrival (wheels-down).

When you see "Estimated 11:42 PM" in a flight tracker, that's the ETA.

OOOI — the ground-truth events

• Out — pushed back from the gate.
• Off — wheels-up.
• On — wheels-down.
• In — at the gate.

These are derived from sensor data on the aircraft (parking brake release, weight on wheels), and form the official record airlines report.

Less common but useful

• ELT — Emergency Locator Transmitter (not a time acronym; it's the device that activates in a crash).
• ETE — Estimated Time Enroute (how long the flight itself takes).
• EFC — Expect Further Clearance (used in holding patterns).

What you'll see in a tracker

FlightyFlow shows STD, ETD, and live updated ETA. The Live Activity surfaces the most relevant time at a glance — usually ETA on approach.