How big can your carry on for an airplane ride be? And can you find me a unique bag that I can find on luggage racks too?

This depends on the airlines that you are traveling with, I have listed  for you some of the airlines and how much you can bring on to their plane's.

• Delta Airlines:
  

If your carry on bag doesn't meet these size and weight restrictions it must be checked, and all checked baggage rules will apply. Your bag must:

•  Weigh less than 40 pounds (18 kg).
•  Not exceed 45 inches (length + width + height), or 115 cm.
•  Fit easily in our SizeCheck® unit (approximately 22"x14"x9", or 56x36x23 cm).
•  Fit in an overhead bin or underneath the seat in front of you.

Personal Items

You're allowed one personal item from this sample list:

• Purses, briefcases, camera cases, and diaper bags
• Laptop computers (can’t be checked and must be carried on)
• Items of a similar or smaller size to those above
  

Other Carry on Items Allowed

You may also bring these items on board. They do not count toward your personal item.

•  Food items for immediate consumption
•  Assistive devices such as wheelchairs or crutches
•  One box or bag of duty free merchandise
•  A coat, jacket, or umbrella
  

Allegiant Air:
Carry on bags must comply with the following baggage regulations:

1. Each e-ticketed passenger is allowed to carry on the aircraft one bag
   plus one personal item.
2. The dimensions for a carry on bag must not exceed 9" H x 14" W x 22" D.
3. The bag must be able to fit under your seat or in the overhead compartment.

US Airway's:

• Up to 45 in/115 cm (14 x 9 x 22 in or 36 x 23 x 56 cm)
• Up to 40 lbs/18 kg

I have also listed for you some luggage rack bags that you can fit all your items in. I hope you have a great trip and if you need anymore help, please let me know!