I’m not sure we should be discussing military strategy in an unsecured environment but if the DoD doesn’t care I won’t either. The Houthis have at least Sa6 and Sa3 Anti aircraft missile system and have employed them against US aircraft. The Houthus also have shot down the MQ9 reapers which are what was discussed in the signal chat. Here’s a video of the congressional hearing about it https://youtu.be/BUHCY0b1gG8

They have anti aircraft missles and have used them successfully.