Billions of riders, each carrying an IP packet.
Someone actually wrote a paper about using pigeons for that. They have high latency, but with advantages like a built-in collision avoidance system and not being restricted to line-of-sight transmission. See RFC 1149 ("IP over Avian Carriers") of the Internet Engineering Task Force.
Even worse, somebody actually implemented it, successfully sending an ICMP echo ("ping") request.
Not doing TCP/IP itself, but even better a pigeon won a transmission race vs. an ISP using DSL once, moving 4 GB of data 40 miles. The bird won using a 4 GB SD card.
The highest bandwidth available now is a 747.
A packet (planeload) of paper records to India for data entry, and a couple boxes of tapes back. much faster and more secure than bouncing signals off satellites or squeezing them down a wire.