Via Air Travel
    - Companies: Delta Airlines, United Airlines
- Duration: Approximately 5 hours (including layovers)
- Distance: 930 kilometers (578 miles)
- Costs: Around 200 - 300 EUR (depending on booking time and class)
- Roads/Routes: Not applicable
Pro Tip: Book in advance and opt for early morning flights to ensure availability and best prices.
Via Car
    - Companies: N/A (personal vehicle or rental)
- Duration: Approximately 11 hours
- Distance: 1,020 kilometers (634 miles)
- Costs: Rental car: 50 - 80 EUR per day + fuel (approx. 80 EUR for the trip)
- Roads/Routes: US-87 S, I-25 S
Pro Tip: Make planned stops at scenic viewpoints along I-25, like the Garden of the Gods in Colorado Springs, to break up the drive and enjoy the views.
Final Recommendation
For this journey from Billings, MT to Hayden, CO, the most efficient travel mode is air travel due to the substantial distance and time savings. However, if you prefer a scenic drive and flexibility, consider renting a car and enjoy the beautiful landscapes along the way. Ensure to check flight schedules and road conditions ahead of your journey.