This Airdrop contract designed to distribute ERC20 tokens to users efficiently and securely. The contract allows the owner to manage airdrops by whitelisting users, enabling them to claim tokens, or sending tokens directly to multiple users. It is perfect for projects that want to engage their community by distributing tokens fairly and transparently.

Key Features:

1. Whitelisting for Airdrop Participation:
   The contract allows the owner to whitelist users, making sure only authorized participants can claim the airdrop.

2. Claimable Airdrop:
   Once whitelisted, users can claim their airdrop tokens directly by interacting with the contract, making the process simple and transparent.

3. Bulk Airdrop:
   The owner can send tokens to multiple users at once with a single transaction, saving time and reducing gas fees.

4. Direct Airdrop:
   Tokens can also be sent directly to users without them needing to claim or be whitelisted, allowing for more flexibility in token distribution.

5. Adjustable Airdrop Amount:
   The owner has the ability to change the token amount each user will receive in the airdrop, providing flexibility for different distribution strategies.

6. Toggle Between Claimable and Direct Airdrop:
   The contract allows the owner to toggle between claimable airdrop mode (where users claim their tokens) and direct airdrop mode (where tokens are sent directly).

7. Leftover Token Withdrawal:
   The owner can safely withdraw any leftover tokens from the contract after the airdrop is complete, ensuring efficient token management.