Interesting question in life: Why is there no signal jammer on the plane?
Although the signal jammer is called a signal "blocker", it is essentially a signal "jammer" and a high-power jammer. The reason why mobile phones cannot be used on planes is to prevent mobile phone signals from interfering with aircraft communication. To install a "blocker" is to install a huge source of interference. So, there will be no such device on the plane!