I have a slightly different take on this question. Other answers have noted that it's good to express something of your personality, but I would add to that that you might want to consider what image you are projecting.

Bear in mind that it's very common amongst the hacker community to have stickers related to the frameworks you like working with. This could be a great conversation starter, particularly if they're technologies that you might not be actively using at your job (e.g. maybe you're using Javascript at work but are really into Clojure, or Elixir; maybe you're using Python at work but love R, ggplot and dplyr). Most people at my work actually have stickers on their work laptops by the way, my old work laptop looked like this (haven't gotten any stickers on my new Macbook yet):

If your laptop has a SQL Server or Powershell stickers on it, I'll probably make some judgements about you.

If you don't have tech-related stickers, and you do have non-tech stickers, I might wonder whether you are really passionate about tech or this is just your day job and you don't really care about it. So bear this in mind.

Also you mention that you have some airplane stickers. Do they look like this:

Or this:

People will make judgements about your politics and values based on this. I personally would be more inclined to hire you if you had the cutesey image, but maybe if you're going for jobs in defence or investment banks or something you would want the second (?).

So my advice would be that you should decorate your personal laptop how you want, but you should think about the kind of image of yourself this will project.

I have a slightly different take on this question. Other answers have noted that it's good to express something of your personality, but I would add to that that you might want to consider what image you are projecting.

Bear in mind that it's very common amongst the hacker community to have stickers related to the frameworks you like working with. This could be a great conversation starter, particularly if they're technologies that you might not be actively using at your job (e.g. maybe you're using Javascript at work but are really into Clojure, or Elixir; maybe you're using Python at work but love R, ggplot and dplyr). Most people at my work actually have stickers on their work laptops by the way, my old work laptop looked like this (haven't gotten any stickers on my new Macbook yet):

If your laptop has a SQL Server or Powershell stickers on it, I'll probably make some judgements about you.

As other answers have noted, tech-related stickers are somewhat of an "ingroup signifier"/coolness on the hacker scene, so if you don't have tech-related stickers, and you do have non-tech stickers, I might wonder whether you are kind of new to the tech scene. Or maybe you don't really care about the tech scene. It's your choice whether you want to try and fit in in this way, but bear this in mind.

Also you mention that you have some airplane stickers. Do they look like this:

Or this:

People will make judgements about your politics and values based on this. I personally would be more inclined to hire you if you had the cutesey image, but maybe if you're going for jobs in defence or investment banks or something you would want the second (?).

So my advice would be that you should decorate your personal laptop how you want, but you should think about the kind of image of yourself this will project.