Drive or Fly: Castle Rock, CO to Longmont, CO?

Side-by-side comparison of driving versus flying for this route. Costs, time, and trade-offs at a glance.

Driving wins

Medium

No scheduled commercial flights found for DEN–BJC. At 66 miles, driving is the only practical option.

Passengers:

Vehicle:

Drive

Door to Door

1h 21m

Distance

66 mi

Total Cost

$50

CO2

27 kg

Cost Breakdown

Diesel$15

Hotel (1 room, 0 nights) $0

Meals (1 pax, 1 day) $35

+ No luggage restrictions or TSA lines

+ Comfortable one-day drive

+ Stop anywhere along the route

+ Have your own car at the destination

+ Likely faster door-to-door than flying

− Wear and tear on vehicle

− Fuel price fluctuations

Plan the drive

Fly

Door to Door

3h 27m

7m in the air

Air Distance

56 mi

Total Cost

$122

CO2

14 kg

Door-to-Door Timeline

Castle Rock, CO → DEN 53m

Check-in & Security 90m

Flight 7m

Arrival & Baggage 30m

BJC → Longmont, CO 27m

Cost Breakdown

Ticket (1 pax @ $122) $122

Airports

Castle Rock, CO DEN — Denver International Airport 35 mi, ~53m drive

Longmont, CO BJC — Rocky Mountain Metropolitan Airport 18 mi, ~27m drive

No scheduled flights found

No commercial flights between DEN and BJC. Flight estimates above are theoretical.

+ Less physical fatigue

+ Predictable arrival time

− Airport security and check-in overhead

− No scheduled commercial flights found for this route

− Luggage fees and restrictions

− Less flexibility for stops along the way

Bus

FlixBus

Door to Door

2h 49m

1h 5m on road

Total Cost

CO2

3 kg

Route

Greyhound US0560S

Door-to-Door Timeline

Castle Rock, CO → Denver Union Station Bus Concourse (DEN6) 41m

Boarding 15m

Bus ride 65m

Arrival 10m

Harmony Transfer Centre (FON6) → Longmont, CO 38m

Cost Breakdown

Ticket (1 pax @ $6) $6

Estimated based on distance. Check flixbus.com for current prices.

Stations

From DEN6 — Denver Union Station Bus Concourse 27 mi, ~41m drive

To FON6 — Harmony Transfer Centre 25 mi, ~38m drive

Service

Direct

Frequency

~7/week

+ Usually the cheapest option

+ Wi-Fi and power outlets on board

+ No driving fatigue — relax or work en route

+ Much lower carbon footprint than driving or flying

− Limited schedule — about 7 trips per week

− Travel time longer than driving

− Need transportation to/from station

− Less flexibility than driving

At a Glance

	Drive	Fly	Bus
Door-to-door time	1h 21m	3h 27m	2h 49m
Total cost (1 person)	$50	$122	$6
Carbon footprint	27 kg CO₂	14 kg CO₂	3 kg CO₂
Flexibility	High	Low
Luggage	Unlimited	Restricted
Reliability	Weather dependent	Data unavailable

Drive data: OSRM routing, EIA fuel prices

Flight data: Statistical estimate

Airports: OurAirports

Transit: FlixBus GTFS — fares estimated

Confidence: Medium — airports identified, fares estimated

Costs are estimates. Actual flight prices vary by airline, date, and booking time. Drive costs based on OSRM routing, EIA fuel prices. Computed Apr 13, 2026.

Decided to drive? See the full trip plan from Castle Rock, CO to Longmont, CO with stops, fuel costs, and turn-by-turn directions.