I am writing a book mostly about the history of my local airport. This will include the changes from the earliest airlines and airports til today. What I want to know, for example, I write about the change in food they were serving to include some of my memories about airline food I had or would that be considered a personal opinion and not allowed in this type of book? Would including any personal knowledge or experiences be OK? The book will be non fiction.
The short answer is yes, you can include this type of material. But it really depends on your audience and the scope of the book. You may not want to do it.
If you're writing a very fact-based formal history, it would be odd to suddenly jump to an anecdote about eating fruit salad while flying. If you interview people to include their personal stories (or get them from publications and other research), then including your own memories makes more sense.
As an example, take the nonfiction book Hidden Figures, about black female mathematicians and engineers who worked at NASA around the time the US made it to the moon. Margot Lee Shetterly uses a multitude of sources, including interviews. The book is filled with both facts and personal stories from the women involved.
What about Shetterly's voice? She doesn't work at NASA and she's too young to have been a part of these events. Yet she's part of the larger community where these scientists lived and worked. Her family knew some of them. Shetterly does inject her personal experience, but only when directly relevant. For example, in the introduction when talking about how she came to write the book.
If you were involved in the history of this airport in any way (including, for example, coming out on opening day as a child, or working towards zoning changes), then include yourself as a source. If your stories are about airports or airlines in general, it might be better to leave it be.
For a more folksy book, you have a lot more leeway. If your stories are compelling enough to stand on their own, then you might want to incorporate them. Or you could frame the book as a personal story you're telling about the history. I don't necessarily recommend these styles, but they are options.
Any book or article can be written with either personified (first-person) or non-personified narration. You just have to select one way or the other.
Typically, reader can tell from the very start if the author presents him/her self or not, and whether the entire book or article is written through the prism of a personal experience. If your situation, it may be odd if you cover most of the book in a dry third-person narration, and then start extensively using "I".
Thus, you probably would want to introduce yourself to the reader at the very beginning, and describe how you personally connected to the airport.
But maybe this narrative shift is exactly what you want, and this change of narration would be similar to breaking the "fourth wall".