On BP medication, a value of 131/90mmHg is within normal range. You can travel without any doubt.
Next Steps
Stress, caffeine and other factors may hinder your BP values. It is advisable to check your BP after relaxing in a seated position for about 10mins.
Health Tips
You can continue monitoring as usual once a month. Since currently BP is under control, there is nothing to worry. Continue your BP medication as prescribed.