The summary

Claim about 2017 inauguration crowd size contradicted by aerial photography and transit data.

The fact-check

Aerial photos comparing 2009 and 2017 inaugurations showed substantially smaller attendance in 2017. DC Metro ridership figures backed this up.

Truth on the record

Estimates from crowd scientists placed attendance at roughly 300,000 to 600,000, far below both the 2009 inauguration and the claimed figure.