I guess it depends how high or low and the cause of it and other problems.
If flying then blood pressure should be under control.
Risk of DVT is a serious consideration if blood pressure is high and problems from blood pressure dropping are not the kind of thing you want to have at high altitudes with limited medical care available.
I'd advise anyone with blood pressure problems to check withtheir doctor before flying (and insurance!) for advice, preventative measures etc...
Lol ,Niceboy ! as I wrote the question that crossed my mind,but at the time I couldn't think of an other way to word it.I wondered how long it would take for a reply like yours.THANKX for the laugh.