First, decide what is missing.
Look for a separate spare, a key tucked into another bag, or a key left with someone at home. If you can see it inside the car, you have an access problem rather than an all-keys-lost replacement job. If it disappeared during the trip, note the last place you remember having it.
Match the place to the right contact.
SEA's official Customer Care page directs terminal and TSA-checkpoint lost property to the airport's Lost and Found. For an item left on an aircraft, contact the airline. For a hotel shuttle or independent parking operation, contact that operator. Keep a useful description of the key and any tag ready.
Describe where the car actually is.
The phrase at SeaTac airport can mean terminal parking, a hotel or a lot several streets away. Have the operator's name, parking level or row, and vehicle details available. Check access arrangements before requesting an outside service. LockReach is not the airport's official assistance service and does not claim access to restricted areas.
If no working key remains.
Have the year, make and model ready, together with proof of ownership or authority. Ask what a replacement key needs to include: a cut blade, starting capability and remote functions may involve different work. Confirm compatibility and availability before ordering a fob or arranging a tow.
Rental car? Start with the rental company.
Its assistance process and authorization come first. Do not assume that independent work will be covered or that a locksmith can simply replace any rental key. Tell the company whether the key is inside, lost or damaged.
Make the next trip a little easier.
Keep a working spare separate from the key you take. Save the parking confirmation and note where you left the car. A photograph of the parking sign is more useful than a memory of which elevator you used after a long flight.
Keep looking and planning as two separate tasks.
A lost-property report may help recover the original key, but it does not establish when it will be found. At the same time, asking about replacement does not commit you to buying a fob before compatibility and availability are known. Work out whether a spare can reach you and what you need in order to continue the trip.
Keep the operator or airline reference with the key description. If the plan changes because the key is found, let anyone arranging work know before a visit or part order goes ahead.
Compare a complete replacement with a complete replacement.
One option may include the fob, blade and programming; another may quote only a part. Ask about all agreed functions, access to the parked vehicle and any additional charges. Check what can be done about the missing key on the specific vehicle. Producing a new key and removing every form of old-key access are not automatically identical tasks.
TAKE THIS WITH YOU
Lost property, vehicle entry and key replacement are three different starting points.