If it is above 100 meters, the trail will be yellow, and with an increase in altitude, will be green, and so on. If the aircraft's position surpasses 2500 meters in altitude, the trail will be light blue, and will then change to dark blue, purple, and finally red for the highest possible altitude.

Excellent question! The colors on a flight’s path on Flightradar24 and similar trackers represent the altitude (or sometimes the speed) of the aircraft at each point along its recorded track. The most common scheme is altitude-based, which is what you’ll see by default.

Here’s a breakdown of the standard color coding:

1. By Altitude (Most Common Default)

The path is colored in a gradient from takeoff to landing, showing how high the plane is flying.

• Purple / Pink: Lowest altitude. This is used for the very beginning of the climb after takeoff and the very end of the descent before landing. You’ll see it near airports.
• Green: Low to medium altitude. Continuing the climb or starting the initial descent.
• Yellow: Medium to high altitude. Often represents cruising levels, but not the highest.
• Orange: High altitude. Typical cruising altitude for many flights.
• Red / Dark Red: Very high altitude. Used for the highest cruising levels, typically for long-haul jets (e.g., above 35,000 feet).

Think of it like a rainbow from cold to hot: Low (cool/purple) → High (hot/red).

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2. By Speed (An Option You Can Select)

In the website or app settings, you can often change the trail color mode to represent ground speed.

• Blue / Light Blue: Slowest speed. Taxiing, holding patterns, or slow approaches.
• Green: Moderate speed. Climbing or descending phases.