For guests flying into Denver, you will fly into the Denver International Airport (DIA).
Please use your room block. You can access it through this link: https://book.passkey.com/e/51001114
If you're flying into Denver International Airport, the RTD A Line commuter rail runs from the airport directly to Union Station, which is less than a mile from The Westin Denver Downtown. The train runs every 15 minutes during peak hours, and every 30 minutes otherwise. The ride takes about 40-minutes, and costs $10 for a one-way ticket.