Shipping lightweight clay blocks by air express involves a few considerations to ensure they arrive safely and efficiently:

1. Packaging: Use sturdy packaging that protects the clay blocks from impact and compression during transit. Ensure the packaging is secure and can withstand handling during air shipping.

2. Documentation: Prepare all necessary shipping documentation, including airway bills, customs declarations (if applicable), and any other required paperwork for international shipments.

3. Weight and Size Restrictions: Check with your chosen air express carrier for any weight and size restrictions they have for shipments. Ensure your clay block packages comply with these restrictions to avoid delays or additional charges.

4. Shipping Method: Choose an air express service that meets your delivery timeline requirements. Options may include standard air express or expedited services depending on the urgency of delivery.

5. Tracking and Insurance: Opt for shipping services that offer tracking and insurance for your shipment. This provides visibility into the shipment's progress and protects against loss or damage during transit.

6. Customs Clearance: Be aware of any customs regulations and clearance procedures for shipping clay blocks internationally. Provide accurate information and documentation to facilitate smooth customs clearance.

By following these steps and working closely with your chosen air express carrier, you can ensure that your lightweight clay blocks are shipped efficiently and reach their destination in good condition.