Getting startup money is not the only reason to write a business plan; there are other just-as-important reasons.
For a winning deck, take a look at the pitch deck template created by Silicon Valley legend, Peter Thiel see it here that I recently covered. In order to do so you will have to provide a solid case for your business idea which makes your executive summary all the more important.
Implementation plan - outline the schedule for taking your business from the planning stage to opening your doors.
Keep things as brief as possible and entice your audience to learn more about your company. Full-length resumes should be appended to the plan.
No one has the time nor desire to bog themselves down in inches thick of paper, unless they are already pretty sure they want to invest. This is not an advertisement or slogan targeted to the masses on Facebook or a billboard.
If it's poorly written, it will also be the last thing they read, as they set the rest of your business plan aside unread. Finally, if you are raising money or taking out loans, you should highlight the money you need to launch the business.
Executive summaries may be more common for traditional businesses pursuing traditional forms of financing. This is a brief that precedes a business plan when seeking new partners, business loans or a an early round of funding for a startup venture.