You have got now aeroplane. That's nice. But you cannot reach even the material planets. So if you want to go to the spiritual planet, then you can make an aeroplane which has speed of the mind. Or the speed of the air. Those who are physicists, they know what is the speed of air, what is the speed of light. So above this speed, the speed of mind. Those who are physicists, they know how speedy is air and light. The mind is still more speedy. You have got experience. Now you are sitting here. Immediate, within a second, you can go to America, USA, India. Immediately you can go to your home, you can see things—with mind, of course; the mind speed. So the Brahma-saṁhitā says that even if you can manufacture one aeroplane which has the speed of the mind, which has the speed of the air—panthās tu koṭi-śata-vatsara-sampragamyaḥ—and with that speed you go on for many millions of years, still you will not find where is Goloka Vṛndāvana. Still, you'll not find. Panthās tu koṭi-śata-vatsara-sampragamyo vāyor athāpi manaso muni-puṅgavānām (Bs. 5.34).
It is not that the previous ācāryas and others, they did not know what is aeroplane, what is speed, how to run. Don't think foolishly, as if they have manufactured. It is nothing, third, not even fourth class, tenth class. There were so nice aeroplanes. Now here is the suggestion that you can manufacture an aeroplane which can run on the speed of mind. Now here is a suggestion—do it. You can manufacture an aeroplane which may run at the speed of the air. They are thinking that at the speed of the light, if we can manufacture one aeroplane, still, it will take forty thousands of years to reach the topmost planet. They're thinking, if it is possible.
But so far we can see, those who are busy with bolts and nuts, how this dull brain they can manufacture such things? That is not possible. It requires another brain. The yogīs can go. The yogīs can go. Just like Durvāsā Muni. He went to Vaikuṇṭhaloka, and he saw personally Lord Viṣṇu in the Vaikuṇṭhaloka for being excused, because His disc was after him to kill. He insulted a Vaiṣṇava. That is another story. So in this way actually human life is meant for that purpose, to understand God and His potencies and to revive our own relationship with Him. That is the main business. But unfortunately, they are being engaged in factories, in other work, to work like hogs and dogs, and their whole energy is being spoiled. Not only spoiled, but their characters . . . they are working so hard, so after working so hard they must drink intoxication. Then after drinking, they must eat meat. After this combination, they require sex. So in this way, they're kept in the darkness.