Introduction[]
In the Dragon Maid manga, Kanna flies from her home in Saitama, Japan to New York City in a very short timeframe.
It happens on the third page, but I'll provide the two before it and the one after for context.
One
Two
Three
Four
The Calc[]
I would say it's safe to assume it took Kanna from the end of the phone conversation to when Chloe opened the door for her to get there. I'll use the 10-15 second timeframe we use by default for feats which take place between manga panels. Realistically, hanging up then walking across a room probably takes less than that, but you all know how much we love our lowballing!
Saitama is 10826 km away from New York, according to Google.
10 Second Version[]
10826/10 = 1082.6 km/s or Mach 3156 or Massively Hypersonic+
15 Second Version[]
10826/15 = 721.7 km/s or Mach 2104 or Massively Hypersonic+
Conclusion[]
Everyone in the verse is upgraded to Massively Hypersonic+ because Kanna is the physically weakest dragon in the verse.