DFW Airport is about 4.6 times smaller than San Francisco.

San Francisco (including the city proper only) is approximately 121 sq km, while DFW Airport is approximately 27 km² (10 sq mi), making DFW Airport 21.9% the size of San Francisco.
Tip: This to-scale comparison of San Francisco vs. DFW Airport uses the Mercator projection, which distorts the size of regions near the poles.
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