How long after the deadline is overdue that you cannot take a high-speed rail flight is a complex issue, because the specific regulations may differ between different regions, companies or individuals. The following are general answers:

1. In China, there are no clear legal provisions stating that you cannot take the high-speed rail or airplane for a few days overdue.

2. Railways and airlines usually handle passengers who overdue repayment according to their own management regulations.

3. Generally speaking, overdue repayments for more than 90 days will be included in the credit reporting system and may have a negative impact on personal credit records.

4. When your personal credit record is damaged, you may be subject to restrictions, such as being unable to apply for loans, credit cards and other financial services.

5. Banks and financial institutions may cooperate with relevant entities to share overdue customer information to prevent risks.

6. High-speed rail and airlines can decide at their own discretion whether to take restrictive measures, such as refusing to provide services or restricting ticket purchases.

Summary: Currently in China, there are no clear regulations stating how long after the expiration date you cannot take the high-speed rail or airplane. However, late repayments may have a negative impact on a personal credit record and lead to the imposition of restrictions, so timely repayment is an important way to maintain personal credit and avoid inconvenience.

Extended information: The impact of late repayment on personal credit records is a topic of common concern. In China, personal credit records involve all aspects of life, including loans, credit cards, renting houses, etc. Late payments can lower your credit score, which may result in a reduction in your credit limit or denial of financial services. Therefore, it is recommended that everyone maintain a good credit record and make repayments on time to ensure that their credit is not damaged.