LONDON, July 7 (Reuters) - Global airline industry body IATA said that passenger air travel demand remained subdued compared to pre-pandemic levels, with figures showing it was 63% lower in May 2021 than in the same month two years ago. International travel is much more affected by ongoing restrictions than travel within domestic markets like China and Russia, IATA said. IATA director general Willie Walsh called on governments to better co-ordinate between themselves to aid the airline industry"s recovery. "We"re seeing a wide variation in the requirements for things like testing...clearly this is causing great confusion in the minds of consumers," Walsh told a briefing on Wednesday.