The best travel backpack for frequent travelers depends on your specific needs, preferences, and the type of travel you'll be doing. Here are a few highly regarded travel backpacks that are popular among frequent travelers:

1. **Osprey Farpoint/Fairview Series**:
   - The Osprey Farpoint (men's) and Fairview (women's) series are known for their comfort and versatility.
   - These backpacks come in various sizes and feature a zip-off daypack, making them suitable for both short trips and longer journeys.
   - The suspension system and padded straps offer comfort during extended wear.

2. **Tortuga Setout Backpack**:
   - The Tortuga Setout Backpack is designed with organization in mind, featuring a clamshell opening for easy packing and access.
   - It has a laptop compartment, best travel backpack for frequent travelers multiple pockets, and a minimalist yet functional design.
   - The harness system provides comfortable carrying, and it meets most airline carry-on size requirements.

3. **Aer Travel Pack 2**:
   - The Aer Travel Pack 2 is a sleek and streamlined option with a focus on organization and functionality.
   - It offers separate compartments for tech items, clothes, and accessories.
   - The sleek design and urban aesthetics make it a popular choice for city travel.

4. **Peak Design Travel Backpack**:
   - The Peak Design Travel Backpack is designed with innovative features like customizable dividers and expandable capacity.
   - It offers quick access to your gear and a modular system for organizing belongings.
   - The backpack's attention to detail and versatile layout make it a great choice for creative travelers.

5. **Nomatic Travel Bag**:
   - The Nomatic Travel Bag is engineered with organization and versatility in mind.
   - It features a range of pockets, compartments, and removable panels for customizable packing.
   - The backpack's sleek design and durable materials make it suitable for a variety of travel styles.

6. **Gregory Paragon (Men) / Maven (Women) Series**:
   - The Gregory Paragon and Maven series offer a comfortable suspension system and ample storage space.
   - These backpacks are designed for hikers but are also well-suited for frequent travelers who prioritize comfort and support.

7. **Patagonia Black Hole Backpack**:
   - The Patagonia Black Hole Backpack is known for its rugged design and weather-resistant materials.
   - It offers a spacious main compartment, multiple pockets, and a comfortable carrying system.

When choosing a travel backpack, consider factors such as size, carry-on compatibility, durability, organization features, and comfort. It's also a good idea to try on backpacks if possible to ensure they fit well and provide the comfort you need during extended use. Additionally, reading user reviews and seeking recommendations from other frequent travelers can help you find the best travel backpack that suits your travel style and preferences.