Yes it is and it is called bonding of network interfaces.
Some general information about bonding ethernet and wireless
A example for systemd-networkd
But keep in mind that it does not automatically make your network faster.
If you download a file with one connection, it is only as fast as your Ethernet or WiFi link. And of course if you download form the internet only as fast as your internet provider allows.
If you download multiple files or split a file download in multiple connections, it can be faster but only if the source and your internet speed is as fast as your ethernet plus wifi.