Thank you Majestic. Interesting. Friends and family members cheering him on.Mostly just names. The big letters at the top say 祈武運長久 (inoru būunchōkyū), which, if you've been following any of these threads, you know is the most common thing written on these flags.
There are a couple of other phrases
米英必滅 (beieihitsumetsu) destroy the yanks and brits
どうぞ御元気で (dōzo ogenkide) take care of yourself
盡忠報国 (jinchūhōkoku) give all for your country