I work as a radio optimiser for a well known multi national company in the uk. The use of jammers is common and work very well. I don't want to single out a race about this but we find that these are normally installed within mosques to stop the use of them within the vicinity.
Also we've seen in prisons but I digress.
Generally though they are band specific and not wideband. Therefore they would disrupt a gsm 900 signal but not a WCDMA 2100. For one to be on board a plane and block all frequencies for gsm, WCDMA and LTE it would be wideband unless multiple units were on board. Back to the ecr cells, we have them in the uk, or did do at t-mobile in the Highlands and Islands of Scotland. I am surprised they are not deployed in the US.