DES stands for Data Encryption Standard while AES stands for Advanced Encryption Standard. The data block for DES is divided into two parts while the entire data block for AES is only one block and will be processed as just one matrix. They will also have differences in terms of what they will be used for.
The DES can be used on the Feistel Cipher Structure while the AES will work on the Substitution and Permutation Principle. There will also be differences with the type of plaintext that will be used.
The DES will have a standard plaintext of 64 bits while the AES will have a standard plaintext of 128, 192, and 256 bits. You can choose depending on what you currently need.