Connectivity on Board: What Actually Works at Altitude

No. It depends on the system fitted to the specific aircraft rather than on private aviation generally. Older airframes and smaller cabins often have none. Ask what is installed on the tail being sent, not on the operator's fleet, because it varies aircraft by aircraft.

Ground-based systems talk to cell towers, so they work over land and stop at the coastline. Satellite systems keep working over oceans and remote regions. Satellite costs more and performance varies with the network and the latitude, but it is the only option once you leave the coast.

On most aircraft with connectivity, yes, and unlike an airliner nobody will stop you. Voice quality depends on the system, and on a satellite link there can be noticeable delay. If a call matters, say so at booking so the aircraft is chosen accordingly.

On a modern satellite system usually yes, on an older one often not. Bandwidth is shared across everyone on board, so a cabin full of people streaming will degrade a call. Treat it as a good hotel connection rather than a home one.

Sometimes. Some operators include it, others bill by the megabyte or by the hour, and the charges can be significant on satellite systems. It is worth confirming how it is billed before the flight rather than discovering it on the invoice.

Rarely without interruption. Coverage gaps happen over oceans, at high latitudes and during climb and descent, and the handover between networks can drop a session. Plan to work in blocks rather than assume a continuous connection.