1. Logbook
First things first, if you don't already have a logbook you need one! You can even log your first Discovery Flight. Every hour counts.
This is essentially your pilot resumé and it is required to log your hours to prove that you received training and endorsements from your flight instructor. You'll log every flight so that you can keep track of hours.
2. Kneeboard
During each flight, you'll take many quick notes and you need a kneeboard, pen and paper in flight. For example, before taxiing out to the runway you'll need clearance from the ground controller. They'll give you instructions that you might want to jot down such as taxi directions, departure frequency, altitude and much more.
Your kneeboard is a staple of your flight bag.
3. Headset
You need a headset as soon as possible once you've decided to pursue flight training. There are many different options. Probably the most popular headset for new pilots is from David Clark because it their headsets are affordable, durable, and longlasting. Plus the headsets come with a warranty if any repairs are necessary in the first few years.
Aviation headsets come in different brands and sizes, and have different features like Bluetooth or noise-cancelling ability. These features are nice, but not crucial for a new pilot.
3. FAR/AIM
Another staple of your pilot bag is the FAR/AIM 2021: Federal Aviation Regulations/Aeronautical Information Manual. Oral exams and flight lessons are 'open book' so you can look up answers to regulations, requirements, and much more. However, you can't easily look up answers if you don't have it with you!
Each year, a new FAR/AIM is published. You'll need to ensure you have the most up to date book in your possession.
4. E6B and/or Electronic Flight Computer.
Sure, you can use an electronic flight computer, but check ride examiners are known to "fail" your gadgets in flight, since you should ALWAYS have a backup and have the skills to use it.
The E6B Flight computer does not rely on batteries and will never fail you. You'll use it during your checkride and written exam. However, an electronic flight computer is easy to use and convenient.
A prepared pilot will have BOTH an electronic flight computer AND a manual E6B so that you always have tools at your disposal.
This electronic light weight, slender flight computer will easily fit in your flight bag and be handy during flights.
5. Oral Exam Guide
You'll need to buy several books to study. Private Pilot Oral Exam Guide: The comprehensive guide to prepare you for the FAA checkride is necessary to review questions that may be asked during your oral exam.
The information in this book is absolutely vital to know if you plan on becoming a safe, informed pilot.
6. ACS: Airman Certification Standards: Private Pilot - Airplane
You'll need to read through the ACS to know what subjects and skills you'll be tested on during your checkride. The ACS is a great resource to review subjects you know and make note of subjects you still need to learn. An instructor and checkride examiner can ask you any questions related to subjects in the ACS.
You can find the ACS online for free, but it's nice to have a physical copy to write notes in or carry with you for quick reference.
7. Pilot's Handbook of Aeronautical Knowledge
Studying at home consistently will save you time and money in your flight lessons. The first book you should study out of is the Pilot's Handbook of Aeronautical Knowledge because it will offer you a strong foundation for learning. Subjects included in this textbook include
ADM (aeronautical decision making), aerodynamics, flight controls, weather, and airport operations.
The Pilot's Handbook of Aeronautical Knowledge and The Airplane Flying Handbook go hand in hand. You need both. You refer back and forth between these two books that provide vital information for you to become a safe, knowledgable pilot.