Late Monday, Verizon and AT&T agreed to a two-week delay rolling out their new 5G technology.

Related: Airbus and Boeing express concerns over 5G interference in US

The technology was slated to launch on Wednesday, but in response to fears that the 5G service will impair airline safety – and amid threats from the Federal Aviation Administration (FAA) to ground or divert flights at a time when the travel industry is already playing catch-up from recent weather and Covid-related flight disruptions – the telecom companies agreed to a pause.

Here’s what you need to know about the controversy:

What is 5G?

5G is the newest generation of cellular network, following 4G, which was introduced in late 2009 and is used on most US cellphones today. Nearly every 10 years since 1980, a new generation network has arrived, offering faster speeds and expanded capabilities. At the simplest level, 1G allowed for phone calls, 2G brought messaging, and 3G provided internet access. Today, on 4G, users can download apps, stream video, and more, with relative ease and speed.

The fifth generation is expected to offer new levels of speed – making it possible, for example, to download a movie to one’s phone in seconds – and allow more devices to be connected to a network at once. The latter is increasingly important in our crowded cellular landscape. (Ever been in a concert or stadium unable to send messages?)

“Those types of data rates could enable virtual reality applications or autonomous driving cars,” Harish Krishnaswamy, an associate professor of electrical engineering at Columbia University, told Live Science.

Why is the US airline industry concerned about 5G?

To execute the upgrade, cellular networks plan to move operations on to a new band of radio frequencies called the C-Band. Last year, Verizon and AT&T spent a combined $67bn acquiring the C-Band spectrum licenses needed to upgrade their networks to 5G, according to Forbes.

But some aircraft regulators worry that planes’ radio altimeters, which measure how far above ground a plane is to help pilots land their crafts in low-visibility situations and also operate on C-Band frequencies, could be disturbed by 5G.

Can 5G and the aviation industry coexist?

The Federal Communications Commission (FCC), the FAA and telecom carriers all agree that 5G and airline travel can exist together. In fact, they already do in nearly 40 countries.

The telecom companies have pointed out that there have not been any accidents in other countries where 5G is operational and American airlines regularly fly to those countries.