If you're running a graphical program, perhaps you should avoid sudo, as it can only ask you for your password via a terminal window, which is not good for graphical programs. (Unless you are launching said programs from a terminal.) I used to recommend gksu or gksudo, but sadly both programs have been discontinued, and are no longer available in recent versions of Ubutnu. You can instead use policykit to run the program as root using pkexec airvpn. That too requires a password, but can prompt for a password with a graphical pop-up window,and thus does not depend on the password being typed into a terminal.
If you don't want to enter your password every time, here are some tips on how to execute a program as root without typing your password.
setuid
If the airvpn executable is a binary file (as opposed to a text file), you should be able to use the chmod command to change the file permissions to activate the setuid mode, meaning it will always run as the user who owns it. (To make sure that user is root, run sudo chroot $(which airvpn).) This will not require a password, and will not require you to do any of the steps below. It will, however, require you to run the following command: sudo chmod u+s $(which airvpn). However, this trick does not work with text files (python programs, shell scripts, etc.). Also, if you ever update this file, you will probably have to do this again. And again the next time you update it. And again...
Make a sudo config file
BTW, sudo (and by extension gksudo and gksu, which both use the same configurations as sudo) and policykit (which can execute program as root using pkexec) can both be programmed to run a program without the need to enter a password. IDK how to do this with policykit, but I can teach you how to achieve this with sudo. Before you continue, you should have a root shell running in the background, just in case something goes wrong. (You may lose your ability to use sudo at all, see below). Create a text file in the /etc/sudoers.d directory. You can call it whatever you want, as long as it doesn't have a . character, and doesn't end with a ~ character.
Before I continue, I should warn you that you'll need to know the path to your airvpn executable. If you enter which airvpn into your terminal, it should tell you where this file is. Assuming it's /usr/bin/airvpn, you can type:
%admin ALL = NOPASSWD:/usr/bin/airvpn
and save it in the /etc/sudoers.d directory. It's probably a good idea to use the chmod command to set the file permissions to 0440. You can do that by running (as root) chmod 0440 file, replacing "file" with the name of the newly-created file.
Now, open a new terminal, and test this new configuration by running sudo airvpn. (The reason the word "new" is in bold is because sudo might not ask you for a password if you've already executed a sudo command in an existing terminal, even if you haven't successfully configured sudo to avoid asking you for a password.) If you were able to do this in a new terminal, you've successfully made it possible to execute airvpn without a password. Now all you have to do is change your startup item to run sudo airvpn, and you'll be good to go. This will work regardless of whether the executable file is a binary file or a text file. Also, you should only need to do this once, regardless of how often you update this program.
Oh no! It didn't work, and now sudo gives me errors!
If something goes wrong, and you lose your ability to use sudo to execute anything as root, you can delete your newly-created file, and sudo should behave as it did before. (Remember when I advised you to keep a root shell running? You'll probably need it to delete that file. Of course, you could execute a root shell by running pkexec su, and then use that to delete the file. Or, if the root account has a password, su should do.)
gksudo replacement
Although gksudo may be dead, there is a way to make a similar replacement yourself. Step one, install the ssh-askpass package: sudo apt install ssh-askpass. Then, create a shell script (using whatever your favorite text editor is), with the following:
#!/bin/sh
export SUDO_ASKPASS=/usr/lib/ssh/x11-ssh-askpass
exec sudo "$@"
You can save it as gksudo. Now, you need to make that script executable, and copy it somewhere where you can execute it. You could combine the he install command will let you do both of those things at the same time: sudo install -o 0 -g 0 -m 0755 ./install /usr/local/sbin. (If you don't have a /usr/local/sbin directory, you might want to make one: sudo mkdir -p /usr/local/sbin.) You may also want to run rm install, so that you don't have a useless second copy lying around.
Now you can type gksudo airvpn, and you'll get a non-terminal prompt to type your password. You can re-use this to make an application launcher, a startup item, or whatever else. Since this script relies on sudo as a backend, any configurations you make to sudo will apply here, as well. Thus, this could become a fallback in case your sudo config fails - unless you can't do anything with sudo, in which case you're on your own. (So, for example, if your /etc/sudoers.d/* file gets deleted for whatever reason.)
