Close calls around the world show that Russian and Chinese pilots want 'batting practice' against the US, top commanders say

• The US military is reporting frequent unsafe intercepts of its planes by Russian and Chinese jets.
• The intercepts reflect a desire to challenge the US and assess its capabilities, US commanders say.
• They come as the jets and weapons the US Air Force relies on for air superiority continue to age.

Russian and Chinese jets have crowded, buzzed, and even collided with US aircraft in hotspots around the world in recent months in a series of encounters that reflect a greater willingness to challenge the US amid heightened tensions with both countries, top US military commanders say.